Catálogo de publicaciones - revistas

<jats:title>Losing its character</jats:title> <jats:p> The eastern Eurasian Basin of the Arctic Ocean is on the far side of the North Pole from the Atlantic, but it is becoming more like its larger neighbor as the climate warms. Polyakov <jats:italic>et al.</jats:italic> show that this region is also evolving toward a state of weakened stratification with increased vertical mixing, release of oceanic heat, and less sea ice. These changes could have considerable impacts on other geophysical and biogeochemical aspects of the Arctic Ocean system and presage a fundamentally new Arctic climate state. </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="6335" page="285" related-article-type="in-this-issue" vol="356" xlink:href="10.1126/science.aai8204">285</jats:related-article> </jats:p>

<jats:title>Multiple images of a type Ia supernova</jats:title> <jats:p> General relativity indicates that any sufficiently massive object bends the path of light passing by it. This effect is known as gravitational lensing. Goobar <jats:italic>et al.</jats:italic> have identified a supernova that is strongly lensed by a foreground galaxy, causing it to be highly magnified and splitting the light into four separate images. What is more, it is a type Ia supernova, a well-studied variety with reliable properties that can be used to constrain models of the lensing. This distinctive object will enable cosmological measurements and can be used to probe the distribution of mass in the foreground galaxy. </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="6335" page="291" related-article-type="in-this-issue" vol="356" xlink:href="10.1126/science.aal2729">291</jats:related-article> </jats:p>

<jats:title>A nonlinear peek into electronic symmetry</jats:title> <jats:p> Strong interactions among electrons in some materials can cause them to assume configurations that are less symmetric than the underlying crystal lattice. These so-called electronic nematic states usually have inversion symmetry, but theorists have predicted that in metals with strong spin-orbit coupling, the inversion symmetry can be lost. Harter <jats:italic>et al.</jats:italic> teased out the symmetry of the electronic order in the compound Cd <jats:sub>2</jats:sub> Re <jats:sub>2</jats:sub> O <jats:sub>7</jats:sub> (see the Perspective by Dodge). They found that a known structural transition in this material is a consequence of another, previously hidden electronic order that breaks inversion symmetry. </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="6335" page="295" related-article-type="in-this-issue" vol="356" xlink:href="10.1126/science.aad1188">295</jats:related-article> ; see also p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6335" page="246" related-article-type="in-this-issue" vol="356" xlink:href="10.1126/science.aam8369">246</jats:related-article> </jats:p>

<jats:title>Low-temperature methane reactions</jats:title> <jats:p> Methane is a potential feedstock for more valuable products. The strong carbon-hydrogen bonds of methane can be activated by heterogeneous catalysts but often at temperatures that make it difficult to control reactions selectively. Liang <jats:italic>et al.</jats:italic> show that methane, adsorbed on the stoichiometric IrO <jats:sub>2</jats:sub> (110) under ultrahigh-vacuum conditions, reacts with exposed iridium atoms to break the carbon-hydrogen bonds at temperatures as low as 150 K. On heating, the surface fragments react cleanly with surface oxygen to form carbon dioxide, carbon monoxide, and water. </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="6335" page="299" related-article-type="in-this-issue" vol="356" xlink:href="10.1126/science.aam9147">299</jats:related-article> </jats:p>

<jats:title>Watching nanomaterials transform in time</jats:title> <jats:p> Real-time analysis of chemical transformations of nanoparticles is usually done with electron microscopy of a few particles. One limitation is interference by the electron beam. Sun <jats:italic>et al.</jats:italic> monitored the oxidation of iron nanoparticles in solution by using small- and wide-angle x-ray scattering and molecular dynamics simulations (see the Perspective by Cadavid and Cabot). These methods revealed the formation of voids within the nanoparticles, diffusion of material into and out of the nanoparticles, and ultimately the coalescence of the voids. </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="6335" page="303" related-article-type="in-this-issue" vol="356" xlink:href="10.1126/science.aaf6792">303</jats:related-article> ; see also p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6335" page="245" related-article-type="in-this-issue" vol="356" xlink:href="10.1126/science.aan0979">245</jats:related-article> </jats:p>

<jats:title>Safe anaerobic metabolism</jats:title> <jats:p> Naked mole-rats live in large colonies deep underground in hypoxic conditions. Park <jats:italic>et al.</jats:italic> found that these animals fuel anaerobic glycolysis with fructose by a rewired pathway that avoids tissue damage (see the Perspective by Storz and McClelland). These results provide insight into the adaptations that this strange social rodent has to make for life underground. They also have implications for medical practice, particularly for understanding how to protect tissues from hypoxia. </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="6335" page="307" related-article-type="in-this-issue" vol="356" xlink:href="10.1126/science.aab3896">307</jats:related-article> ; see also p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6335" page="248" related-article-type="in-this-issue" vol="356" xlink:href="10.1126/science.aan1505">248</jats:related-article> </jats:p>

<jats:title>Drug efflux machinery inherited asymmetrically</jats:title> <jats:p> In dividing bacterial cells, asymmetric distribution of cell wall constituents occurs between mother cells and their progeny. Asymmetric distribution of efflux machinery in a growing population of bacterial cells results in heterogeneity in antibiotic resistance. One consequence is that in the presence of low levels of antibiotic, older cells tend to live longer than younger cells. Using a microfluidic device to trap and measure dividing cells, Bergmiller <jats:italic>et al.</jats:italic> showed that AcrAB-TolC, the main multidrug efflux pump of <jats:italic>Escherichia coli</jats:italic> , clusters at the pole of older cells (see the Perspective by Barrett <jats:italic>et al.</jats:italic> ). As cell division proceeds and daughter cells age, they too gradually accumulate polar efflux pumps. </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="6335" page="311" related-article-type="in-this-issue" vol="356" xlink:href="10.1126/science.aaf4762">311</jats:related-article> ; see also p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6335" page="247" related-article-type="in-this-issue" vol="356" xlink:href="10.1126/science.aan0348">247</jats:related-article> </jats:p>

<jats:title>Gut anaerobes protect against pathogen invasion</jats:title> <jats:p> Intestinal infections are a common problem for young animals. One explanation is that the protective gut microbiota is not fully established in infants. How the microbiota might protect against pathogens is unclear. Kim <jats:italic>et al.</jats:italic> found that members of the group of strictly anaerobic, spore-forming bacteria known as clostridia protect neonatal mice against diarrhea-causing pathogens. The protective effect is enhanced by giving mice the metabolite succinate in drinking water. Succinate favors colonization of the neonatal gut by cluster IV and XIVa clostridia and concomitantly excludes <jats:italic>Salmonella typhimurium.</jats:italic> </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="6335" page="315" related-article-type="in-this-issue" vol="356" xlink:href="10.1126/science.aag2029">315</jats:related-article> </jats:p>

<jats:title>Ancestral legacy effects</jats:title> <jats:p> Environmental change can critically affect the lifestyle, reproductive success, and life span of adult animals and their for generations. Klosin <jats:italic>et al.</jats:italic> showed that in the nematode worm <jats:italic>Caenorhabditis elegans</jats:italic> , exposure to high temperatures led to expression of endogenously repressed copies of genes—sometimes called “junk” DNA. This effect persisted for &gt;10 generations of worms. The changes in chromatin occurred in the early embryo before the onset of transcription and were inherited through eggs and sperm. </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="6335" page="320" related-article-type="in-this-issue" vol="356" xlink:href="10.1126/science.aah6412">320</jats:related-article> </jats:p>