Catálogo de publicaciones - revistas

<jats:title>How to observe fault injections in real time</jats:title> <jats:p> Faults in the ground are known to deform in response to procedures such as wastewater injection that change the pore pressure. Guglielmi <jats:italic>et al.</jats:italic> took a crack at monitoring this process in real time with a controlled fluid injection into an inactive fault (see the Perspective by Cornet). Reactivating the dead fault induced aseismic slip, which triggered small earthquakes. These observations can inform models of how friction is related to slip rate. The technique can also be applied to field-scale monitoring of seismicity-inducing wastewater injections. </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="6240" page="1224" related-article-type="in-this-issue" vol="348" xlink:href="10.1126/science.aab0476">1224</jats:related-article> ; see also p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6240" page="1204" related-article-type="in-this-issue" vol="348" xlink:href="10.1126/science.aab3820">1204</jats:related-article> </jats:p>

<jats:title>Quality manufacture beats quality control</jats:title> <jats:p> For semiconductor nanocrystals, tight control over particle size is needed to obtain particles with uniform properties. However, post-synthesis purification methods can be difficult and costly. Hendricks <jats:italic>et al.</jats:italic> present a family of substituted thioureas as a class of chalcogen precursors (see the Perspective by Hens). The rate of reactivity is connected to the specific chemistry of the precursor, making it possible to synthesize metal chalcogenide nanocrystals, such as PbS, with a specific size, narrow size distribution, and full conversion of the reactants. </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="6240" page="1226" related-article-type="in-this-issue" vol="348" xlink:href="10.1126/science.aaa2951">1226</jats:related-article> ; see also p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6240" page="1211" related-article-type="in-this-issue" vol="348" xlink:href="10.1126/science.aab0866">1211</jats:related-article> </jats:p>

<jats:title>Molybdenum doping drives high activity</jats:title> <jats:p> Platinum (Pt) is an effective catalyst of the oxygen reduction reaction in fuel cells but is scarce. One approach to extend Pt availability is to alloy it with more abundant metals such as nickel (Ni). Although these catalysts can be highly active, they are often not durable because of Ni loss. Huang <jats:italic>et al.</jats:italic> show that doping the surface of octahedral Pt <jats:sub>3</jats:sub> Ni nanocrystals with molybdenum not only leads to high activity (∼80 times that of a commercial catalyst) but enhances their stability. </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="6240" page="1230" related-article-type="in-this-issue" vol="348" xlink:href="10.1126/science.aaa8765">1230</jats:related-article> </jats:p>

<jats:title>Taking in more sun</jats:title> <jats:p> Most efforts to grow superior films of organic-inorganic perovskites for solar cells have focused on methylammonium lead iodide (MAPbI <jats:sub>3</jats:sub> ). However, formamidinium lead iodide (FAPbI <jats:sub>3</jats:sub> ) has a broader solar absorption spectrum that could ultimately lead to better performance. Yang <jats:italic>et al.</jats:italic> grew high-quality FAPbI <jats:sub>3</jats:sub> films by starting with a film of lead iodide and dimethylsulfoxide (DMSO) and then exchanging the DMSO with formamidinium iodide. Their best devices achieved power conversion efficiencies exceeding 20%. </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="6240" page="1234" related-article-type="in-this-issue" vol="348" xlink:href="10.1126/science.aaa9272">1234</jats:related-article> </jats:p>

<jats:title>Change was in the air</jats:title> <jats:p> The atmospheric fraction of molecular oxygen gas, O <jats:sub>2</jats:sub> , currently at 21%, is thought to have varied between around 35 and 15% over the past 500 million years. Because O <jats:sub>2</jats:sub> is not a greenhouse gas, often this variability has not been considered in studies of climate change. Poulson and Wright show that indirect effects of oxygen abundance, caused by contributions to atmospheric pressure and mean molecular weight, can affect precipitation and atmospheric humidity (see the Perspective by Peppe and Royer). These effects may thus have produced significant changes in the strength of greenhouse forcing by water vapor, surface air temperatures, and the hydrological cycle in the geological past. </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="6240" page="1238" related-article-type="in-this-issue" vol="348" xlink:href="10.1126/science.1260670">1238</jats:related-article> ; see also p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6240" page="1210" related-article-type="in-this-issue" vol="348" xlink:href="10.1126/science.aac5264">1210</jats:related-article> </jats:p>

<jats:title>Cooperating brain regions express similar genes</jats:title> <jats:p> When the brain is at rest, a number of distinct areas are functionally connected. They tend to be organized in networks. Richiardi <jats:italic>et al.</jats:italic> compared brain imaging and gene expression data to build computational models of these networks. These functional networks are underpinned by the correlated expression of a core set of 161 genes. In this set, genes coding for ion channels and other synaptic functions such as neurotransmitter release dominate. </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="6240" page="1241" related-article-type="in-this-issue" vol="348" xlink:href="10.1126/science.1255905">1241</jats:related-article> </jats:p>

<jats:title>Not too fast and not too slow</jats:title> <jats:p> Moths are typically active during dawn and dusk when light levels are low and vision is challenging. Slower visual response times can allow for greater light sensitivity, but flying insects are both moving and tracking moving targets, making such tradeoffs potentially problematic. Using a combination of modeling and experiments, Sponberg <jats:italic>et al.</jats:italic> show that moths are able to avoid this potential decrease in visual acuity (see the Perspective by Warrant). This is because the point at which their perception of movement would be compromised is just above the natural frequency at which flowers sway. Thus, insect vision is precisely adapted to the light and movement conditions of their environment. </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="6240" page="1245" related-article-type="in-this-issue" vol="348" xlink:href="10.1126/science.aaa3042">1245</jats:related-article> ; see also p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6240" page="1212" related-article-type="in-this-issue" vol="348" xlink:href="10.1126/science.aab2185">1212</jats:related-article> </jats:p>