Catálogo de publicaciones - revistas

<jats:title>Making sure leftover light gets in</jats:title> <jats:p> Bacteria that harvest sunlight through photosynthesis are everywhere and are vital for absorbing carbon dioxide. Like plants in a jungle, these cells have to compete for access to light. Gan <jats:italic>et al.</jats:italic> found that one species of such cyanobacteria, <jats:italic>Leptolyngbya</jats:italic> , survives on the scraps of leftover light that other photosynthetic cells can't use. When the light is crowded out by competing organisms, <jats:italic>Leptolyngbya</jats:italic> changes the pathways in its cells that make the light-harvesting molecules and remodels them into structures that can use redder light at longer wavelengths that is unused by other cells. </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="6202" page="1312" related-article-type="in-this-issue" vol="345" xlink:href="10.1126/science.1256963">1312</jats:related-article> </jats:p>

<jats:title>Orbits don't forget their chaotic pasts</jats:title> <jats:p> Many exoplanets orbit in planes that don't correspond to their star's spin axis. This phenomenon may be the fossil record of a dynamical history. Storch <jats:italic>et al.</jats:italic> demonstrate in simulations that the evolution of a star's spin is key in determining how its planets' orbits are eventually oriented. A binary companion body can drive a hot Jupiter to migrate inward, which induces chaotic behavior in the stellar spin axis and feedback down the line. If we can accurately replicate the statistics observed in planetary surveys, we may understand better how planets form. </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="6202" page="1317" related-article-type="in-this-issue" vol="345" xlink:href="10.1126/science.1254358">1317</jats:related-article> </jats:p>

<jats:title>Compressive, ductile ceramic nanolattices</jats:title> <jats:p> Ceramics are strong and stiff, but their limited ability to stretch like putty or steels makes them unsuitable for many engineering applications. Meza <jats:italic>et al.</jats:italic> constructed ceramic nanolattices from aluminum oxide, in which the beams are designed to stretch rather than bend. A key parameter in lattice design is the ratio of the wall thickness to the beam radius. When that ratio is small enough, compressing the beams does not break them. That way, the nanolattices can be highly compressed and recover to something close to their original shape when the stress is removed. </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="6202" page="1322" related-article-type="in-this-issue" vol="345" xlink:href="10.1126/science.1255908">1322</jats:related-article> </jats:p>

<jats:title>Scheduling hydrogen release from water</jats:title> <jats:p> Photosynthesis splits water to provide protons and electrons for plant growth; oxygen is a by-product. When chemists split water, they're also more interested in making fuel, and the simplest product is hydrogen (a combination of protons and electrons). One challenge is keeping the reactive hydrogen and oxygen product streams separate. Rausch <jats:italic>et al.</jats:italic> present a scheme that captures the protons and electrons in a molecular cluster of silico-tungstic acid. Later, they expose the cluster to platinum, coaxing the acid into releasing hydrogen. Eliminating the mixing risk increases the potential for household use. </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="6202" page="1326" related-article-type="in-this-issue" vol="345" xlink:href="10.1126/science.1257443">1326</jats:related-article> </jats:p>

<jats:title>Sheltered black hole seeds grow faster</jats:title> <jats:p>Astrophysicists have struggled to find a way to grow supermassive black holes within the first billion years of the universe, in the first 6% of its current age. These objects power the extremely bright and distant quasars whose light from that era has finally reached us. To grow a black hole so massive so quickly seemed to violate the expected balance of both radiation pressure and angular momentum. Alexander and Natarajan report that the predicted accretion rate can be exceeded with the help of a protective gas cloud at the heart of a star cluster. There, the radiation from accretion is reverted back onto the black hole, enabling a phase of supraexponential growth for a brief 10 million years.</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="6202" page="1330" related-article-type="in-this-issue" vol="345" xlink:href="10.1126/science.1251053">1330</jats:related-article> </jats:p>

<jats:title>Manipulating a defect in diamond</jats:title> <jats:p> Like magnetic storage in today's classical computers, tiny “magnets” associated with electronic and nuclear states—spins—are promising qubits (quantum bits) for the future. Electronic spins in special defects in diamond called nitrogen-vacancy (NV) centers are one example. Whereas most applications focus on the least energetic (ground) state of an NV center, Bassett <jats:italic>et al.</jats:italic> explored the properties of the higher-energy (excited) state (see the Perspective by Childress). They used light pulses to bring the system into the excited state and to vary the time it stayed there. In this way, they could both deduce the electronic structure of the excited state and manipulate the ground state spin. Similar methods may be applicable to other quantum information systems. </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="6202" page="1333" related-article-type="in-this-issue" vol="345" xlink:href="10.1126/science.1255541">1333</jats:related-article> ; see also p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6202" page="1247" related-article-type="in-this-issue" vol="345" xlink:href="10.1126/science.1257840">1247</jats:related-article> </jats:p>

<jats:title>All-optical magnetic state switching</jats:title> <jats:p> Magneto-optical memory storage media, such as hard drives, use magnetic fields to change the magnetization of memory bits, but the process is slow. Light can often reveal information about the magnetization state of a sample, such as its field direction. Lambert <jats:italic>et al.</jats:italic> show that under the right circumstances, light can also switch the magnetization state of a thin ferromagnetic film. Using light pulses instead of magnetic fields led to ultrafast data memory and data storage. </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="6202" page="1337" related-article-type="in-this-issue" vol="345" xlink:href="10.1126/science.1253493">1337</jats:related-article> </jats:p>

<jats:title>Moral homeostasis in real life vs. the lab</jats:title> <jats:p> Individuals who witnessed a moral deed are more likely than nonwitnesses to perform a moral deed themselves and are also more likely to allow themselves to act immorally. Hofmann <jats:italic>et al.</jats:italic> asked smartphone users to report their encounters with morality (see the Perspective by Graham). Most moral judgment experiments are lab-based and don't allow for conclusions based on what people experience in their daily lives. This field experiment revealed that people experience moral events frequently in daily life. A respondent's ideology influenced the kind of event reported and the frequency, which is consistent with moral foundations theory. </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="6202" page="1340" related-article-type="in-this-issue" vol="345" xlink:href="10.1126/science.1251560">1340</jats:related-article> ; see also p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6202" page="1242" related-article-type="in-this-issue" vol="345" xlink:href="10.1126/science.1259500">1242</jats:related-article> </jats:p>

<jats:title>Costa Rican birds of a feather lost together</jats:title> <jats:p> Evolutionary history is lost when land is converted for farming, and recently evolved species may cope better with changing land use. Frishkoff <jats:italic>et al.</jats:italic> compared bird diversity over 12 years in three different kinds of landscape in tropical Central America. They mapped their data onto the bird evolutionary tree and found that more evolutionary branches were lost in intensive agricultural landscapes than in mixed landscapes. In turn, mixed landscapes lost more evolutionary branches than forest reserves. This is not just because of species loss; in fact, mixed agricultural landscapes contained similar numbers of species to those in forest reserves. Evolutionary history is lost because the more evolutionarily distinct species—those with fewer extant relatives and a longer evolutionary history—are more likely to become extinct in agricultural land. </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="6202" page="1343" related-article-type="in-this-issue" vol="345" xlink:href="10.1126/science.1254610">1343</jats:related-article> </jats:p>

<jats:title>Patterns of life in the ocean wave</jats:title> <jats:p> The open ocean is not uniform. The seas teem with unseen life that has evolved distinctive patterns of species distribution, much as the land-bound world contains a spectrum of biological provinces. Taking data from genome studies, Hellweger <jats:italic>et al.</jats:italic> devised a model showing how marine bacteria diversified throughout the world's oceans into stable geographic provinces independently of natural selection (see the Perspective by Giovannoni and Nemergut). All that is needed to create these distributions are mutations and ocean currents. </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="6202" page="1346" related-article-type="in-this-issue" vol="345" xlink:href="10.1126/science.1254421">1346</jats:related-article> ; see also p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6202" page="1246" related-article-type="in-this-issue" vol="345" xlink:href="10.1126/science.1259467">1246</jats:related-article> </jats:p>