Catálogo de publicaciones - revistas

<jats:title>Maximizing elements for your genome</jats:title> <jats:p> The accumulation of mutations is typically limited by selective parameters. One such parameter is the elements needed to build proteins and molecules to maintain cells. Examining the underlying carbon, oxygen, and nitrogen content for different amino acids, Shenhav <jats:italic>et al.</jats:italic> examined the selective pressure resulting from nutrient limitation (see the Perspective by Polz and Cordero). The authors identified “resource-driven” selection as a purifying selective force associated with environmental nutrient availability, particularly nitrogen, and determined the impact of mutations on the organismal nutritional budget. From this constraint, the authors have proposed that the structure of the genetic code across organisms reflects the mutational impact on elemental resources. </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="6517" page="683" related-article-type="in-this-issue" vol="370" xlink:href="10.1126/science.aaz9642">683</jats:related-article> ; see also p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6517" page="655" related-article-type="in-this-issue" vol="370" xlink:href="10.1126/science.abf2588">655</jats:related-article> </jats:p>

<jats:title>Ancient amphibians preserved in amber</jats:title> <jats:p> Extant amphibians are represented by three fairly simple morphologies: the mostly hopping frogs and toads, the low-crawling salamanders, and the limbless caecilians. Until the early Pleistocene—and for more than 165 million years—there was another group, the albanerpetontids. We know little about this group because amphibian fossils are poorly preserved, and previous specimens from this group are both rare and mostly badly damaged. Daza <jats:italic>et al.</jats:italic> describe a set of fossils preserved in amber showing that this group was unusual both in their habitat use (they may been climbers) and their feeding mode, which appears to have been convergent with the ballistic feeding now seen in chameleons (see the Perspective by Wake). </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="6517" page="687" related-article-type="in-this-issue" vol="370" xlink:href="10.1126/science.abb6005">687</jats:related-article> ; see also p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6517" page="654" related-article-type="in-this-issue" vol="370" xlink:href="10.1126/science.abe7826">654</jats:related-article> </jats:p>

<jats:title>Epidemiology in southern India</jats:title> <jats:p> By August 2020, India had reported several million cases of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), with cases tending to show a younger age distribution than has been reported in higher-income countries. Laxminarayan <jats:italic>et al.</jats:italic> analyzed data from the Indian states of Tamil Nadu and Andhra Pradesh, which have developed rigorous contact tracing and testing systems (see the Perspective by John and Kang). Superspreading predominated, with 5% of infected individuals accounting for 80% of cases. Enhanced transmission risk was apparent among children and young adults, who accounted for one-third of cases. Deaths were concentrated in 50- to 64-year-olds. Incidence did not change in older age groups, possibly because of effective stay-at-home orders and social welfare programs or socioeconomic status. As in other settings, however, mortality rates were associated with older age, comorbidities, and being male. </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="6517" page="691" related-article-type="in-this-issue" vol="370" xlink:href="10.1126/science.abd7672">691</jats:related-article> ; see also p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6517" page="663" related-article-type="in-this-issue" vol="370" xlink:href="10.1126/science.abe9707">663</jats:related-article> </jats:p>

<jats:title>Low-noise organic photodetectors</jats:title> <jats:p> Although the high performance and low cost of visible light silicon photodetectors suffice for most applications, their small size and rigid nature are not optimal for applications such as wearable sensors. Organic photodetectors can be flexible and large in area but are often noisy. Fuentes-Hernandez <jats:italic>et al.</jats:italic> found that optimized choices of the semiconductor and electrode materials that improve diode characteristics enable organic photodetectors that can detect low light levels with low noise. </jats:p> <jats:p> <jats:italic>Science</jats:italic> , this issue p. <jats:related-article issue="6517" page="698" related-article-type="in-this-issue" vol="370">698</jats:related-article> </jats:p>

<jats:title>Switching on topology</jats:title> <jats:p> Ways to control and design topological features in various systems are being studied intensively because the resulting properties tend to be robust against things such as scattering and defects, endowing the system with topological protection. Maczewsky <jats:italic>et al.</jats:italic> now look to another regime in optics to show that optical nonlinearity can induce a topological change in the properties of a photonic lattice. At low excitation power, probe light uniformly leaks into the rest of the lattice, an optically trivial phase. Above a threshold power, optical nonlinearity induces a topological change in the properties of the photonic lattice, and probe light is confined to propagate along the edge of the structure. These results illustrate a route to dynamically control the propagation of light. </jats:p> <jats:p> <jats:italic>Science</jats:italic> , this issue p. <jats:related-article issue="6517" page="701" related-article-type="in-this-issue" vol="370">701</jats:related-article> </jats:p>