Catálogo de publicaciones - revistas

<jats:title>Ionizing photons escape a lensed galaxy</jats:title> <jats:p> Young, hot stars emit ultraviolet radiation, which can ionize a neutral gas. The first generation of stars converted most of the intergalactic gas in the Universe from neutral to ionized form during the epoch of reionization less than a billion years after the Big Bang. Rivera-Thorsen <jats:italic>et al.</jats:italic> took advantage of a gravitational lensing system to observe 12 images of the same star-forming region in a distant galaxy and determined the fraction of ultraviolet photons that escape into the intergalactic medium. Although this galaxy is younger than the epoch of reionization, the results provide clues about how ultraviolet photons escape their host galaxies and contribute to the reionization process. </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="6466" page="738" related-article-type="in-this-issue" vol="366" xlink:href="10.1126/science.aaw0978">738</jats:related-article> </jats:p>

<jats:title>Bound to rock</jats:title> <jats:p> Organic matter binds to phyllosilicates, a process which affects both its transport and chemical stability. How does that affect the fate of terrestrial organic carbon that enters the ocean? Blattmann <jats:italic>et al.</jats:italic> show that organic carbon derived from soils is stripped from mineral surfaces upon discharge and dispersal into the ocean, whereas organic matter derived from ancient rocks is preserved there. Their results show that preservation of continentally derived organic matter in marine sediments is controlled largely by phyllosilicate mineralogy. </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="6466" page="742" related-article-type="in-this-issue" vol="366" xlink:href="10.1126/science.aax5345">742</jats:related-article> </jats:p>

<jats:title>Trapped atoms to probe gravity</jats:title> <jats:p> Exploiting the wave nature of atoms in an interferometer setup can be used to provide a precise measure of gravity. The precision is limited to the time scale of the interferometric measurement, which in turn is limited to the distance that the atoms drop, typically just over a couple of seconds for a 10-meter drop tower. Xu <jats:italic>et al.</jats:italic> describe a trapped atom interferometer in which the interrogation time of the interferometric measurements can be extended to 20 seconds. The new interferometer design and subsequent improved precision can be used to make fundamental tests of general relativity as well as precision measurements of other potentials. </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="6466" page="745" related-article-type="in-this-issue" vol="366" xlink:href="10.1126/science.aay6428">745</jats:related-article> </jats:p>

<jats:title>Maintaining the bandgap</jats:title> <jats:p> The bandgap of the black α-phase of formamidinium-based lead triiodide (FAPbI <jats:sub>3</jats:sub> ) is near optimal for creating high-efficiency perovskite solar cells. However, this phase is unstable, and the additives normally used to stabilize this phase at ambient temperature—such as methylammonium, caesium, and bromine—widen its bandgap. Min <jats:italic>et al.</jats:italic> show that doping of the α-FAPbI <jats:sub>3</jats:sub> phase with methylenediammonium dichloride enabled power conversion efficiencies of 23.7%, which were maintained after 600 hours of operation. Unencapsulated devices had high thermal stability and retained &gt;90% efficiency even after annealing for 20 hours at 150°C in air. </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="6466" page="749" related-article-type="in-this-issue" vol="366" xlink:href="10.1126/science.aay7044">749</jats:related-article> </jats:p>

<jats:title>Toward less brittle degradable plastic</jats:title> <jats:p> Bacteria produce a class of polyesters, termed polyhydroxyalkanoates, that are particularly appealing on account of how easily they undergo biodegradation. Unfortunately, these polymers also tend to be overly brittle for many applications. Tang <jats:italic>et al.</jats:italic> report that a molecular lanthanide catalyst can sequentially polymerize chiral and then achiral diastereomers to form polyhydroxyalkanoate varieties that are substantially more ductile. The catalyst selectively produces these copolymers directly from diastereomeric mixtures of monomers, obviating the need for a wasteful separation process ahead of time. </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="6466" page="754" related-article-type="in-this-issue" vol="366" xlink:href="10.1126/science.aax8466">754</jats:related-article> </jats:p>

<jats:p>A weekly roundup of information on newly offered instrumentation, apparatus, and laboratory materials of potential interest to researchers.</jats:p>