Catálogo de publicaciones - revistas

<jats:title>A volcanic source of variation</jats:title> <jats:p> The Atlantic Multidecadal Oscillation (AMO), a 50- to 70-year quasiperiodic variation of climate centered in the North Atlantic region, was long thought to be an internal oscillation of the climate system. Mann <jats:italic>et al.</jats:italic> now show that this variation is forced externally by episodes of high-amplitude explosive volcanism. They used an ensemble of climate models to evaluate the causes of the AMO, finding that volcanos are the most important influence, and that there is no evidence to show that it has been internally generated during the last millennium. </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="6533" page="1014" related-article-type="in-this-issue" vol="371" xlink:href="10.1126/science.abc5810">1014</jats:related-article> </jats:p>

<jats:title>A red-letter day for RBC research</jats:title> <jats:p> The study of primary human red blood cell (huRBC) disorders such as sickle cell disease (SCD) and infectious diseases such as malaria has been hampered by a lack of in vivo models of human erythropoiesis. Song <jats:italic>et al.</jats:italic> transferred human fetal liver cells into MISTRG mice, which are immunodeficient and are genetically engineered with several human genes involved in hematopoiesis. This approach was unsuccessful because mature huRBCs are rapidly destroyed in the mouse liver. They then used CRISPR-Cas9 to mutate these mice into a fumarylacetoacetate hydrolase–deficient strain, allowing them to replace the mouse liver with engrafted human hepatocytes. These mice exhibited enhanced human erythropoiesis and circulating huRBC survival and could recapitulate SCD pathology when reconstituted with SCD-derived HSCs. </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="6533" page="1019" related-article-type="in-this-issue" vol="371" xlink:href="10.1126/science.abe2485">1019</jats:related-article> </jats:p>

<jats:title>A two-stage lightweighting</jats:title> <jats:p> Dealloying allows voids to be created in metals, decreasing the weight of the material. However, when the solid fraction is below about 30%, the mechanical properties rapidly degrade. Shi <jats:italic>et al.</jats:italic> discovered that two dealloying steps allow for the creation of a silver-gold alloy with a solid fraction as low as 12%. Unexpectedly, this process does not degrade the mechanical properties while allowing for large samples to be synthesized. The strategy should be applicable to other alloy systems, providing a pathway for creating strong and lightweight materials. </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="6533" page="1026" related-article-type="in-this-issue" vol="371" xlink:href="10.1126/science.abd9391">1026</jats:related-article> </jats:p>

<jats:title>Phenazines liberate phosphate</jats:title> <jats:p>Bacteria secrete a wide range of small molecules with chemical reactivity that offers multiple functions in different contexts. Phenazines are commonly considered to be antibiotics, but they can also participate in environmental redox reactions, especially with iron. McRose and Newman found that phenazines, when added exogenously or made by bacteria in situ, can liberate phosphorous (P) in the form of phosphate from mineral surfaces, and that the production of these molecules is regulated by signaling pathways that respond to P limitation. Strains unable to produce these molecules grew more slowly under P limitation but could be rescued by the addition of exogenous phenazines. The authors hypothesize that reductive dissolution of iron oxides has the benefit of liberating P, and that this could be one mechanism of microbial P acquisition in some environments.</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="6533" page="1033" related-article-type="in-this-issue" vol="371" xlink:href="10.1126/science.abd1515">1033</jats:related-article> </jats:p>

<jats:title>A transiting rocky planet 8 parsecs away</jats:title> <jats:p> Most exoplanets have been detected using either the radial velocity (RV) method or the transit method, which provide only limited information on the planet's physical properties. In the rare cases in which both methods detect the same planet, the combination determines the planet's mass, radius, and density. Trifonov <jats:italic>et al.</jats:italic> identified a planet, Gliese 486 b, using both RV and transit data. The host star is a red dwarf only 8 parsecs away, making this one of the closest exoplanet systems known. A rocky super-Earth, Gliese 486 b has an equilibrium surface temperature of 700 kelvin. The authors say that it is observationally favorable for searches for an atmosphere. </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="6533" page="1038" related-article-type="in-this-issue" vol="371" xlink:href="10.1126/science.abd7645">1038</jats:related-article> </jats:p>

<jats:title>Warming autumns, fewer butterflies</jats:title> <jats:p> Many recent studies have revealed sweeping declines in insects over the past few decades. Butterflies are no exception. Forister <jats:italic>et al.</jats:italic> used three different datasets, collected by both experts and community scientists, and found that the number of butterflies has declined over the past 40 years. Although the drivers of decline are complex, the authors found that climate change—in particular, warmer months in the autumn—explain a large portion, even as warming summers actually lead to increases. This work shows that climate change impacts may be insidious and unexpected in their effects. </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="6533" page="1042" related-article-type="in-this-issue" vol="371" xlink:href="10.1126/science.abe5585">1042</jats:related-article> </jats:p>

<jats:title>A heavy black hole in an x-ray binary</jats:title> <jats:p> If a black hole interacts with a binary companion star, the system emits x-rays and can form a radio jet. The masses of black holes in these x-ray binaries are all lower than those detected using gravitational waves, challenging models of black hole formation from massive stars. Miller-Jones <jats:italic>et al.</jats:italic> used radio astrometry to refine the distance to Cygnus X-1, a well-studied x-ray binary. They found a larger distance than previous estimates, raising the mass of the black hole in the system to 21 solar masses. The results challenge the wind mass loss rates implemented in stellar evolution models. </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="6533" page="1046" related-article-type="in-this-issue" vol="371" xlink:href="10.1126/science.abb3363">1046</jats:related-article> </jats:p>