Catálogo de publicaciones - revistas

<jats:title>Resolving whole mitoribosomes</jats:title> <jats:p> Mitochondria probably evolved from a prokaryotic cell living within a proto-eukaryotic cell. Consequently, mitochondria have lost much of their genomic DNA, except for a few genes that require highly divergent mitoribosomes for protein translation. Greber <jats:italic>et al.</jats:italic> and Amunts <jats:italic>et al.</jats:italic> have used cryo–electron microscopy to uncover the structure of this complex (see the Perspective by Beckmann and Hermann) and reveal an unusual mRNA binding channel. The structure supplies clues for how aminoglycoside antibiotics might inhibit mitoribosomes and how mutations in mitoribosomes might cause human disease. </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="6232" page="303" related-article-type="in-this-issue" vol="348" xlink:href="10.1126/science.aaa3872">303</jats:related-article> , p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6232" page="288" related-article-type="in-this-issue" vol="348" xlink:href="10.1126/science.aab1054">288</jats:related-article> ; see also A. Amunts <jats:italic>et al., Science</jats:italic> , 3 April, p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6230" page="95" related-article-type="in-this-publication" vol="348" xlink:href="10.1126/science.aaa1193">95</jats:related-article> </jats:p>

<jats:title>Metal clusters really close-up</jats:title> <jats:p> Atomic force microscopy (AFM) can be used to reveal subatomic structures. By this means, Emmrich <jats:italic>et al.</jats:italic> found that individual copper and iron atoms formed toroidal structures on a copper surface. These shapes arise from the electrostatic attractions in the center of the atoms and Pauli repulsions at their edges. Individual atoms within clusters have underlying surface symmetry and can bind to different surface sites as clusters 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="6232" page="308" related-article-type="in-this-issue" vol="348" xlink:href="10.1126/science.aaa5329">308</jats:related-article> </jats:p>

<jats:title>The polarized mark of magnetic fields</jats:title> <jats:p> Powerful twin jets of plasma often reach more than tens of thousands of light-years from their base in an active galactic nucleus (AGN). Astronomers are still at work investigating what can corral the jets so tightly and propel them so far. Martí-Vidal <jats:italic>et al.</jats:italic> may have found the answer hiding in polarized light signals that show evidence of a phenomenon called Faraday rotation. This measure can indicate the strength of the magnetic field present, which for the AGN PKS 1830-211 is as strong as a few Gauss. The knowledge that magnetic fields have a driving role brings us closer to understanding this phenomenon. </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="6232" page="311" related-article-type="in-this-issue" vol="348" xlink:href="10.1126/science.aaa1784">311</jats:related-article> </jats:p>

<jats:title>Eat your heart out, old galaxies</jats:title> <jats:p> Most galaxies exceeding 100 billion solar masses are dense spheroids that exhibit no star-forming activity in the present day. Nevertheless, galaxies of the same size were actively forming stars when the universe was only a few billion years old. Tacchella <jats:italic>et al.</jats:italic> used integral-field spectroscopy and high-resolution imaging to map the distributions of star formation rates and stellar mass densities within ancient galaxies. Star formation apparently quenched first in the center, while remaining lively in the galactic outskirts, with quenching taking a few billion years to proceed outward. </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="6232" page="314" related-article-type="in-this-issue" vol="348" xlink:href="10.1126/science.1261094">314</jats:related-article> </jats:p>

<jats:title>Massive electrons signify correlations</jats:title> <jats:p> Thirty years on, and the mechanism of superconductivity in copper-oxide superconductors remains a mystery. Knowledge of their normal nonsuperconducting state is also incomplete; however, we do know that the more robust the superconductivity, the higher the magnetic fields required to suppress it. Ramshaw <jats:italic>et al.</jats:italic> studied samples of three different compositions of the copper-oxide YBa <jats:sub>2</jats:sub> Cu <jats:sub>3</jats:sub> O <jats:sub>6+δ</jats:sub> in magnetic fields exceeding 90 T. They found that as the oxygen content increased toward the point of the maximum transition temperature, the conducting electrons became heavier and heavier. This mass enhancement reflected an increase in electronic correlations, which in turn may be a signature of a quantum critical point. </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="6232" page="317" related-article-type="in-this-issue" vol="348" xlink:href="10.1126/science.aaa4990">317</jats:related-article> </jats:p>

<jats:title>Traces of collisions within collisions</jats:title> <jats:p> The Moon is widely accepted to have been created by the collision of a Mars-sized body with Earth. However, information about exactly when this event occurred is still welcome. To find out more, Bottke <jats:italic>et al.</jats:italic> compared models and the meteorite record with estimates of impact heating. When ejecta was thrown off during the main collision, high-velocity kilometer-sized fragments hit and heated main-belt asteroids. Evidence of such collisions emerges when pieces of those asteroids turn up as meteorites on Earth. The model and empirical record converge on 4.48 billion years ago, confirming previous estimates reached by different approaches. </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="6232" page="321" related-article-type="in-this-issue" vol="348" xlink:href="10.1126/science.aaa0602">321</jats:related-article> </jats:p>

<jats:title>Smaller differences and greater extremes</jats:title> <jats:p> Has recent rapid warming in the Arctic affected weather elsewhere in the world? Coumou <jats:italic>et al.</jats:italic> find that some key measures of atmospheric circulation in the Northern Hemisphere have weakened during the summer. This change has been caused by the reduction of the temperature difference between mid-latitudes and the North Pole. As summertime circulation has decreased in intensity, episodes of hot weather have become more persistent because there are fewer storms to bring cooler conditions. </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="6232" page="324" related-article-type="in-this-issue" vol="348" xlink:href="10.1126/science.1261768">324</jats:related-article> </jats:p>

<jats:title>Disappearing faster around the edges</jats:title> <jats:p> The floating ice shelves around Antarctica, which buttress ice streams from the continent and slow their discharge into the sea, are thinning at faster rates. Paolo <jats:italic>et al.</jats:italic> present satellite data showing that ice shelves in many regions around the edge of the continent are losing mass. This result increases concern about how fast sea level might rise as climate continues to warm. If warming continues to cause ice shelves to thin, as they have for the past couple of decades, their disappearance may allow land-based ice to collapse and melt. </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="6232" page="327" related-article-type="in-this-issue" vol="348" xlink:href="10.1126/science.aaa0940">327</jats:related-article> </jats:p>

<jats:title>Dilution solves the recalcitrance question</jats:title> <jats:p> The deep ocean is full of dissolved organic carbon, some of which has remained unchanged for thousands of years. What makes these compounds so resistant to microbial degradation? Perhaps their chemical structures make them intrinsically difficult to metabolize? In contrast, Arrieta <jats:italic>et al.</jats:italic> show that they are simply too dilute to be viable sources of energy for microorganisms (see the Perspective by Middleburg). Further experiments show that if these seemingly recalcitrant organic molecules are concentrated, the ambient microbes can consume them. </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="6232" page="331" related-article-type="in-this-issue" vol="348" xlink:href="10.1126/science.1258955">331</jats:related-article> ; see also p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6232" page="290" related-article-type="in-this-issue" vol="348" xlink:href="10.1126/science.aaa9852">290</jats:related-article> </jats:p>

<jats:title>Gaze into my eyes</jats:title> <jats:p> Humans bond emotionally as we gaze into each other's eyes—a process mediated by the hormone oxytocin. Nagasawa <jats:italic>et al.</jats:italic> show that such gaze-mediated bonding also exists between us and our closest animal companions, dogs (see the Perspective by MacLean and Hare). They found that mutual gazing increased oxytocin levels, and sniffing oxytocin increased gazing in dogs, an effect that transferred to their owners. Wolves, who rarely engage in eye contact with their human handlers, seem resistant to this effect. </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="6232" page="333" related-article-type="in-this-issue" vol="348" xlink:href="10.1126/science.1261022">333</jats:related-article> ; see also p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6232" page="280" related-article-type="in-this-issue" vol="348" xlink:href="10.1126/science.aab1200">280</jats:related-article> </jats:p>