Catálogo de publicaciones - revistas

<jats:title>Neutrons peek into f-electron bands</jats:title> <jats:p> Neutron scattering can be used to tease out the details of collective magnetic excitations that yield well-defined peaks in the data. In principle, it could also be used to look into single-electron band excitations, but collecting enough data to capture broad distributions of intensity is tricky. Goremychkin <jats:italic>et al.</jats:italic> used neutron spectrometers that could efficiently capture a large amount of data by rotating the sample, a crystal of the intermediatevalence compound CePd <jats:sub>3</jats:sub> (see the Perspective by Georges). The measured dynamical magnetic susceptibility, in combination with detailed ab initio calculations, showed the formation of coherent f-electron bands at low temperatures. </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="6372" page="186" related-article-type="in-this-issue" vol="359" xlink:href="10.1126/science.aan0593">186</jats:related-article> ; see also p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6372" page="162" related-article-type="in-this-issue" vol="359" xlink:href="10.1126/science.aar2325">162</jats:related-article> </jats:p>

<jats:title> Dissecting <jats:italic>Plasmodium</jats:italic> drug resistance </jats:title> <jats:p> Malaria is a deadly disease with no effective vaccine. Physicians thus depend on antimalarial drugs to save lives, but such compounds are often rendered ineffective when parasites evolve resistance. Cowell <jats:italic>et al.</jats:italic> systematically studied patterns of <jats:italic>Plasmodium falciparum</jats:italic> genome evolution by analyzing the sequences of clones that were resistant to diverse antimalarial compounds across the <jats:italic>P. falciparum</jats:italic> life cycle (see the Perspective by Carlton). The findings identify hitherto unrecognized drug targets and drug-resistance genes, as well as additional alleles in known drug-resistance genes. </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="6372" page="191" related-article-type="in-this-issue" vol="359" xlink:href="10.1126/science.aan4472">191</jats:related-article> ; see also p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6372" page="159" related-article-type="in-this-issue" vol="359" xlink:href="10.1126/science.aar4189">159</jats:related-article> </jats:p>

<jats:title>Water ice cliffs on Mars</jats:title><jats:p>Some locations on Mars are known to have water ice just below the surface, but how much has remained unclear. Dundas<jats:italic>et al.</jats:italic>used data from two orbiting spacecraft to examine eight locations where erosion has occurred. This revealed cliffs composed mostly of water ice, which is slowly sublimating as it is exposed to the atmosphere. The ice sheets extend from just below the surface to a depth of 100 meters or more and appear to contain distinct layers, which could preserve a record of Mars' past climate. They might even be a useful source of water for future human exploration of the red planet.</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="6372" page="199" related-article-type="in-this-issue" vol="359" xlink:href="10.1126/science.aao1619">199</jats:related-article></jats:p>

<jats:title>A specific interstellar aromatic molecule</jats:title> <jats:p> Aromatic molecules such as polycyclic aromatic hydrocarbons (PAHs) are known to exist in the interstellar medium owing to their characteristic infrared emission features. However, the infrared emission only indicates the general class of molecule, and identifying which specific molecular species are present is difficult. McGuire <jats:italic>et al.</jats:italic> used radio astronomy to detect rotational transitions of benzonitrile emitted from a well-known nearby cloud of interstellar gas (see the Perspective by Joblin and Cernicharo). This molecule may be a precursor to more complex PAHs. The identification of benzonitrile sheds light on the composition of aromatic material within the interstellar medium—material that will eventually be incorporated into new stars and planets. </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="6372" page="202" related-article-type="in-this-issue" vol="359" xlink:href="10.1126/science.aao4890">202</jats:related-article> ; see also p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6372" page="156" related-article-type="in-this-issue" vol="359" xlink:href="10.1126/science.aar4541">156</jats:related-article> </jats:p>

<jats:title>Mesoporous metal-organic frameworks</jats:title> <jats:p> The diffusion limitations on gas storage and catalytic reaction of microporous materials can often be overcome if they are incorporated into a mesoporous structure with much larger pores. Shen <jats:italic>et al.</jats:italic> grew ordered arrays of microcrystals of the ZIF-8 metal-organic framework, in which zinc ions are bridged by 2-methylimidazole linkers, inside a porous polystyrene template. These materials showed higher reaction rates for the Knoevenagel reaction between benzaldehydes and malononitriles and better catalyst recyclability. </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="6372" page="206" related-article-type="in-this-issue" vol="359" xlink:href="10.1126/science.aao3403">206</jats:related-article> </jats:p>

<jats:title>Cholera pathogen zaps competition</jats:title> <jats:p> Many bacterial pathogens inject their hosts with virulence effectors delivered by specialist secretion machines. <jats:italic>Vibrio cholerae</jats:italic> has a type VI secretion system (T6SS) that can be loaded with protein toxins that target eukaryote host cells or kill competing bacteria. Zhao <jats:italic>et al.</jats:italic> discovered that mutant <jats:italic>V. cholerae</jats:italic> lacking a T6SS could not compete against <jats:italic>Escherichia coli</jats:italic> strains in the mouse gut. In contrast, intact <jats:italic>V. cholerae</jats:italic> readily gained a foothold in the gut of young mice, pumping up inflammatory immune responses and prompting more violent symptoms. </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="6372" page="210" related-article-type="in-this-issue" vol="359" xlink:href="10.1126/science.aap8775">210</jats:related-article> </jats:p>

<jats:title>The representation of others in space</jats:title> <jats:p> Different sets of neurons encode the spatial position and orientation of an organism. However, social animals need to know the position of other individuals for social interactions, observational learning, and group navigation. Surprisingly, very little is known about how the position of other animals is represented in the brain. Danjo <jats:italic>et al.</jats:italic> and Omer <jats:italic>et al.</jats:italic> now report the discovery of a subgroup of neurons in hippocampal area CA1 that encodes the presence of conspecifics in rat and bat brains, respectively. </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="6372" page="213" related-article-type="in-this-issue" vol="359" xlink:href="10.1126/science.aao3898">213</jats:related-article> , p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6372" page="218" related-article-type="in-this-issue" vol="359" xlink:href="10.1126/science.aao3474">218</jats:related-article> </jats:p>

<jats:title>The representation of others in space</jats:title> <jats:p> Different sets of neurons encode the spatial position and orientation of an organism. However, social animals need to know the position of other individuals for social interactions, observational learning, and group navigation. Surprisingly, very little is known about how the position of other animals is represented in the brain. Danjo <jats:italic>et al.</jats:italic> and Omer <jats:italic>et al.</jats:italic> now report the discovery of a subgroup of neurons in hippocampal area CA1 that encodes the presence of conspecifics in rat and bat brains, respectively. </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="6372" page="213" related-article-type="in-this-issue" vol="359" xlink:href="10.1126/science.aao3898">213</jats:related-article> , p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6372" page="218" related-article-type="in-this-issue" vol="359" xlink:href="10.1126/science.aao3474">218</jats:related-article> </jats:p>

<jats:title>Rapid hybrid speciation in Darwin's finches</jats:title> <jats:p> Galapagos finches have driven hypotheses of how speciation occurs. Most commonly, it is assumed that natural selection separates species originating from a single population on the basis of variation in traits that confer advantages for survival and reproduction. Lamichhaney <jats:italic>et al.</jats:italic> document a case where cross-species hybridization established a reproductively isolated lineage, which demonstrates a process known as homoploid hybrid speciation in action (see the Perspective by Wagner). The authors used genetic markers and phenotypic analyses to create a pedigree that revealed how a cross-island migrant bred with a native species to form a self-perpetuating hybrid population that was reproductively isolated from both parental species. </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="6372" page="224" related-article-type="in-this-issue" vol="359" xlink:href="10.1126/science.aao4593">224</jats:related-article> ; see also p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6372" page="157" related-article-type="in-this-issue" vol="359" xlink:href="10.1126/science.aar4796">157</jats:related-article> </jats:p>

<jats:title>Architecture of the TRPM subfamily</jats:title> <jats:p> Transient receptor potential melastatin (TRPM) ion channels constitute the largest TRP subfamily and are involved in many physiological processes. TRPM8 is the primary cold and menthol sensor, and TRPM4 is associated with cardiovascular disorders. Yin <jats:italic>et al.</jats:italic> and Autzen <jats:italic>et al.</jats:italic> shed light on the general architecture of the TRPM subfamily by solving the structures of TRPM8 and TRPM4, respectively (see the Perspective by Bae <jats:italic>et al.</jats:italic> ). The three-layered architecture of the TRPM8 channel provides the framework for understanding the mechanisms of cold and menthol sensing. The two distinct closed states of TRPM4, with and without calcium, reveal a calcium-binding site and calcium-binding-induced conformational changes. </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="6372" page="237" related-article-type="in-this-issue" vol="359" xlink:href="10.1126/science.aan4325">237</jats:related-article> , p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6372" page="228" related-article-type="in-this-issue" vol="359" xlink:href="10.1126/science.aar4510">228</jats:related-article> ; see also p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6372" page="160" related-article-type="in-this-issue" vol="359" xlink:href="10.1126/science.aar6205">160</jats:related-article> </jats:p>