Catálogo de publicaciones - revistas

<jats:p> In their comment, Desjarlais <jats:italic>et al</jats:italic> . claim that a small temperature drop occurs after isentropic compression of fluid deuterium through the first-order insulator-metal transition. We show that their calculations do not correspond to the experimental thermodynamic path, and that thermodynamic integrations with parameters from first-principles calculations produce results in agreement with our original estimate of the temperature drop. </jats:p>

<jats:title>Rapid response to tissue damage</jats:title> <jats:p> Damaged plants are susceptible to microbial attack. In response to physical damage, plants proactively generate signal peptides to activate their immune systems. Hander <jats:italic>et al.</jats:italic> examined wound responses in the model plant <jats:italic>Arabidopsis thaliana</jats:italic> . They identified a metacaspase that releases an immunomodulatory signal peptide from its precursor form within 30 seconds of the damage. The metacaspase itself was activated by a burst of calcium released by tissue damage. </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" related-article-type="in-this-issue" xlink:href="10.1126/science.aar7486">eaar7486</jats:related-article> </jats:p>

<jats:p> Celliers <jats:italic>et al</jats:italic> . (Reports, 17 August 2018, p. 677), in an attempt to reconcile differences in inferred metallization pressures, provide an alternative temperature analysis of the Knudson <jats:italic>et al</jats:italic> . experiments (Reports, 26 June 2015, p. 1455). We show that this reanalysis implies an anomalously low specific heat for the metallic fluid that is clearly inconsistent with first-principles calculations. </jats:p>

<jats:title>How activation leads to gating</jats:title> <jats:p> Voltage-gated sodium (Na <jats:sub>v</jats:sub> ) channels are key players in electrical signaling. Central to their function is fast inactivation, and mutants that impede this cause conditions such as epilepsy and pain syndromes. The channels have four voltage-sensing domains (VSDs), with VSD4 playing an important role in fast inactivation. Clairfeuille <jats:italic>et al.</jats:italic> determined the structures of a chimera in which VSD4 of the cockroach channel Na <jats:sub>v</jats:sub> PaS is replaced with VSD4 from human Na <jats:sub>v</jats:sub> 1.7, both in the apo state and bound to a scorpion toxin that impedes fast activation (see the Perspective by Chowdhury and Chanda). The toxin traps VSD4 in a deactivated state. Comparison with the apo structure shows how interactions between VSD4 and the carboxyl-terminal region change as VSD4 activates and suggests how this would lead to fast inactivation. </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" related-article-type="in-this-issue" xlink:href="10.1126/science.aav8573">eaav8573</jats:related-article> ; see also p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6433" page="1278" related-article-type="in-this-issue" vol="363" xlink:href="10.1126/science.aaw8645">1278</jats:related-article> </jats:p>

<jats:title>Sequencing and the single sperm</jats:title> <jats:p> During meiosis, homologous chromosomes undergo doublestrand breaks in DNA that can cross over, shuffling genetic material. However, not every double-strand break resolves in a crossover event. Hinch <jats:italic>et al.</jats:italic> wanted to determine the rules governing DNA recombination. They developed a method to sequence individual mouse sperm and applied it to mice carrying two different alleles of a protein involved in mammalian crossovers. A high-resolution genetic map revealed the relationships between the distribution of crossovers, proteins involved in recombination, and specific factors determining whether a double-strand break becomes a crossover. </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" related-article-type="in-this-issue" xlink:href="10.1126/science.aau8861">eaau8861</jats:related-article> </jats:p>

<jats:title>Automating geoscience analysis</jats:title> <jats:p> Solid Earth geoscience is a field that has very large set of observations, which are ideal for analysis with machine-learning methods. Bergen <jats:italic>et al.</jats:italic> review how these methods can be applied to solid Earth datasets. Adopting machine-learning techniques is important for extracting information and for understanding the increasing amount of complex data collected in the geosciences. </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" related-article-type="in-this-issue" xlink:href="10.1126/science.aau0323">eaau0323</jats:related-article> </jats:p>

<jats:p>Film is a universal language of modern societies. Larger-than-life images, stories, ideas, and characters portrayed in films can speak across the globe. This makes science and technology—which have shaped the modern world but remain little understood and poorly integrated into mainstream culture—a rich subject for film and a goldmine for filmmakers. From the mad scientist films of the '20s and '30s to the postnuclear dystopias of the '50s; and from the ecological disaster flics of the '70s and '80s to the space adventures of recent years, films have periodically reflected society's hopes and fears about science. But we can do better when it comes to dramatizing the great, ongoing human enterprise to understand and enhance the world around and inside us.</jats:p>

<jats:p>A roundup of weekly science policy and related news.</jats:p>

<jats:p>Brain recordings shore up a controversial proposal, but mechanism remains hazy.</jats:p>