Catálogo de publicaciones - revistas

<jats:title>Human-derived neurons provide the answers</jats:title> <jats:p> Pathways involved in energy metabolism and removal of cellular debris by lysosomes play an important role in protecting our brain from degeneration in Parkinson's disease. Burbulla <jats:italic>et al.</jats:italic> identified a toxic cascade of mitochondrial and lysosomal dysfunction in human neurons derived from patients with Parkinson's. The dysfunction was mediated by accumulation of oxidized dopamine and α-synuclein, but it was not found in Parkinson's mouse models, owing to species-specific differences in dopamine metabolism. Inherent species-specific differences between human and mouse neurons emphasize the value of studying human neurons to identify relevant targets for treatment of Parkinson's disease and related synucleinopathies. </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="6357" page="1255" related-article-type="in-this-issue" vol="357" xlink:href="10.1126/science.aam9080">1255</jats:related-article> </jats:p>

<jats:title>Poison frogs resist their own chemical defense</jats:title> <jats:p> Poison frogs produce a neurotoxin that protects them from predation. The frogs, however, run the risk of intoxicating themselves. Studying the frog neurotoxin epibatidine, which binds to acetylcholine receptors, Tarvin <jats:italic>et al.</jats:italic> found a single amino acid substitution. The substitution changes the configuration of the acetylcholine receptor, so that it decreases its sensitivity to the toxin. But acetylcholine signaling is essential for normal life. Expressing frog receptors in human cells revealed that different amino acid substitutions have occurred in different lineages that allow the frog to resist its own toxins while still letting target neurotransmitters function effectively. </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="6357" page="1261" related-article-type="in-this-issue" vol="357" xlink:href="10.1126/science.aan5061">1261</jats:related-article> </jats:p>

<jats:title>High-energy particles are extragalactic</jats:title> <jats:p>Cosmic rays are high-energy particles arriving from space; some have energies far beyond those that human-made particle accelerators can achieve. The sources of higher-energy cosmic rays remain under debate, although we know that lower-energy cosmic rays come from the solar wind. The Pierre Auger Collaboration reports the observation of thousands of cosmic rays with ultrahigh energies of several exa–electron volts (about a Joule per particle), arriving in a slightly dipolar distribution (see the Perspective by Gallagher and Halzen). The direction of the rays indicates that the particles originated in other galaxies and not from nearby sources within our own Milky Way 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="6357" page="1266" related-article-type="in-this-issue" vol="357" xlink:href="10.1126/science.aan4338">1266</jats:related-article> ; see also p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6357" page="1240" related-article-type="in-this-issue" vol="357" xlink:href="10.1126/science.aao5651">1240</jats:related-article> </jats:p>

<jats:title>An early call for plate tectonics</jats:title> <jats:p> The composition of continental crust far back in Earth's history gives us insight into when plate tectonics ramped up and has influenced ocean chemistry. Greber <jats:italic>et al.</jats:italic> looked at titanium isotopes in shales, which form from eroded continental crustal sediments, to estimate the composition 3.5 billion years ago, closer to the origins of Earth. They found a silica-rich composition, which indicates that plate tectonics was happening deep in our distant past. Other changes in crustal composition might be linked to changing ocean chemistry and major events such as the oxygenation of our 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="6357" page="1271" related-article-type="in-this-issue" vol="357" xlink:href="10.1126/science.aan8086">1271</jats:related-article> </jats:p>

<jats:title>Photoemission with a twist</jats:title> <jats:p> Attosecond time-resolved spectroscopy provides the ability to probe the fastest electronic processes in atoms and solids. Yet the photoemission process from solids is not fully understood. Siek <jats:italic>et al.</jats:italic> studied photoemission from the layered van der Waals material WSe <jats:sup>2</jats:sup> and found that electron emission occurs as a sequence of events that are apparently time-ordered with respect to rising angular momentum of the involved initial states (see the Perspective by Yakovlev and Karpowicz). This result will help provide a more detailed picture of the photoemission 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="6357" page="1274" related-article-type="in-this-issue" vol="357" xlink:href="10.1126/science.aam9598">1274</jats:related-article> ; see also p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6357" page="1239" related-article-type="in-this-issue" vol="357" xlink:href="10.1126/science.aao3421">1239</jats:related-article> </jats:p>

<jats:title>Universal scaling for big quakes</jats:title> <jats:p> The amount of energy released as a large fault ruptures provides some clues about the overall size of an earthquake. Meier <jats:italic>et al.</jats:italic> looked at this energy release for more than 100 large earthquakes. Although the overall size of an earthquake cannot be predicted from the rate of energy release, a minimum size can be estimated. Estimating this minimum size could add valuable seconds to early earthquake warning algorithms, helping to avoid damage and save people from injury or death. </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="6357" page="1277" related-article-type="in-this-issue" vol="357" xlink:href="10.1126/science.aan5643">1277</jats:related-article> </jats:p>

<jats:title>Neandertal growth patterns</jats:title><jats:p>The ontogeny of different parts of the Neandertal skeleton has been derived from isolated bones and fragments. Rosas<jats:italic>et al.</jats:italic>present a more complete skeleton of a Neandertal child, aged 7 to 8 years, from a 49,000-year-old site in northern Spain. The skeleton preserves dental, cranial, and postcranial material, allowing the assessment of dental and skeletal maturation with age. Most of the elements indicate an overall growth rate similar to that of modern human children. The main difference between Neandertals and modern humans is in the vertebral column. Also, several features indicate ongoing brain growth. The pattern of vertebral maturation and extended brain growth might reflect the broad Neandertal body form and physiology, rather than a fundamental difference in the overall pace of growth in Neandertals.</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="6357" page="1282" related-article-type="in-this-issue" vol="357" xlink:href="10.1126/science.aan6463">1282</jats:related-article></jats:p>

<jats:title>Helping people and their businesses grow</jats:title> <jats:p> Many lower-income people in developing countries do not receive a wage but instead are self-employed in small firms of fewer than five workers. Helping entrepreneurs to grow small businesses by teaching them formal business skills has yielded mixed results. Campos <jats:italic>et al.</jats:italic> show that teaching entrepreneurial skills to the self-employed works much better in terms of increasing both sales and profits. The entrepreneurial training relies on psychological mechanisms that enhance personal initiative. </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="6357" page="1287" related-article-type="in-this-issue" vol="357" xlink:href="10.1126/science.aan5329">1287</jats:related-article> </jats:p>

<jats:title>If at first you don't succeed, try again</jats:title> <jats:p> Does grit—the combination of perseverance and passion popularized in the media—differ from conscientiousness? Personality traits are embedded early in life and remain relatively stable, whereas grit (at least the passion component) may come and go and thus be malleable. Leonard <jats:italic>et al.</jats:italic> show that infants can learn from adults to persist through failure at arduous tasks (see the Perspective by Butler). Infants who had observed adults struggle for half a minute before activating a toy persisted when given their own complicated toy to play with, in contrast to the lesser grit displayed by infants who had seen only rapid and effortless adult successes. </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="6357" page="1290" related-article-type="in-this-issue" vol="357" xlink:href="10.1126/science.aan2317">1290</jats:related-article> ; see also p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6357" page="1236" related-article-type="in-this-issue" vol="357" xlink:href="10.1126/science.aao6255">1236</jats:related-article> </jats:p>

<jats:title>Multitalented enhancers</jats:title> <jats:p> Productive transcription from DNA demands initiation, elongation, and termination. Enhancers are DNA sequences that loop with promoters to initiate transcription. Chen <jats:italic>et al.</jats:italic> show that enhancers also regulate gene expression by modulating transcription elongation. PAF1, a RNA polymerase II–associated factor, sits on enhancers. This prevents the full activation of the enhancer required for the release of paused polymerase at promoters to achieve successful transcription elongation. </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="6357" page="1294" related-article-type="in-this-issue" vol="357" xlink:href="10.1126/science.aan3269">1294</jats:related-article> </jats:p>