Catálogo de publicaciones - revistas

<jats:p>A host-parasite system indicates how ecological and evolutionary mechanisms shape the distribution of microbes in soil.</jats:p>

<jats:title>Lysine Acetylation Catalog</jats:title> <jats:p> Covalent posttranslational modification is an essential cellular regulatory mechanism by which the activity of proteins can be controlled. Advances in mass spectrometry made it possible for <jats:bold> Choudhary <jats:italic>et al.</jats:italic> </jats:bold> (p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" page="834" related-article-type="in-this-issue" vol="325" xlink:href="10.1126/science.1175371">834</jats:related-article> , published online 16 July) to assess the prevalence of lysine acetylation throughout the whole proteome. Acetylation is much more widespread than previously appreciated and occurs on proteins participating in all sorts of biological functions. Acetylation can influence susceptibility of proteins to phosphorylation and occurs frequently on enzymes that control the modification of other proteins by covalent ubiquitination and on proteins that form large macromolecular complexes. The findings also help to characterize the actions of lysine deacetylase inhibitors, which have shown clinical promise in treatments for cancer. </jats:p>

<jats:title>Gamma-Ray Pulsar Bonanza</jats:title> <jats:p> Most of the pulsars we know about were detected through their radio emission; a few are known to pulse gamma rays but were first detected at other wavelengths (see the Perspective by <jats:bold> <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="5942" page="821" related-article-type="in-this-issue" vol="325" xlink:href="10.1126/science.1178573">Halpern</jats:related-article> </jats:bold> ). Using the Fermi Gamma-Ray Space Telescope, <jats:bold> Abdo <jats:italic>et al.</jats:italic> </jats:bold> (p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" page="840" related-article-type="in-this-issue" vol="325" xlink:href="10.1126/science.1175558">840</jats:related-article> , published online 2 July; see the cover) report the detection of 16 previously unknown pulsars based on their gamma-ray emission alone. Thirteen of these coincide with previously unidentified gamma-ray sources, solving the 30-year-old mystery of their identities. Pulsars are fast-rotating neutron stars. With time they slow down and cease to radiate; however, if they are in a binary system, they can have their spin rates increased by mass transfer from their companion stars, starting a new life as millisecond pulsars. In another study, <jats:bold> Abdo <jats:italic>et al.</jats:italic> </jats:bold> (p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" page="845" related-article-type="in-this-issue" vol="325" xlink:href="10.1126/science.1177023">845</jats:related-article> ) report the detection of gamma-ray emission from the globular cluster 47 Tucanae, which is coming from an ensemble of millisecond pulsars in the cluster's core. The data imply that there are up to 60 millisecond pulsars in 47 Tucanae, twice as many as predicted by radio observations. In a further companion study, <jats:bold> Abdo <jats:italic>et al.</jats:italic> </jats:bold> (p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" page="848" related-article-type="in-this-issue" vol="325" xlink:href="10.1126/science.1176113">848</jats:related-article> , published online 2 July) searched Fermi Large Area Telescope data for pulsations from all known millisecond pulsars outside of stellar clusters, finding gamma-ray pulsations for eight of them. Their properties resemble those of other gamma-ray pulsars, suggesting that they share the same basic emission mechanism. Indeed, both sets of pulsars favor emission models in which the gamma rays are produced in the outer magnetosphere of the neutron star. </jats:p>

<jats:title>Gamma-Ray Pulsar Bonanza</jats:title> <jats:p> Most of the pulsars we know about were detected through their radio emission; a few are known to pulse gamma rays but were first detected at other wavelengths (see the Perspective by <jats:bold> <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="5942" page="821" related-article-type="in-this-issue" vol="325" xlink:href="10.1126/science.1178573">Halpern</jats:related-article> </jats:bold> ). Using the Fermi Gamma-Ray Space Telescope, <jats:bold> Abdo <jats:italic>et al.</jats:italic> </jats:bold> (p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" page="840" related-article-type="in-this-issue" vol="325" xlink:href="10.1126/science.1175558">840</jats:related-article> , published online 2 July; see the cover) report the detection of 16 previously unknown pulsars based on their gamma-ray emission alone. Thirteen of these coincide with previously unidentified gamma-ray sources, solving the 30-year-old mystery of their identities. Pulsars are fast-rotating neutron stars. With time they slow down and cease to radiate; however, if they are in a binary system, they can have their spin rates increased by mass transfer from their companion stars, starting a new life as millisecond pulsars. In another study, <jats:bold> Abdo <jats:italic>et al.</jats:italic> </jats:bold> (p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" page="845" related-article-type="in-this-issue" vol="325" xlink:href="10.1126/science.1177023">845</jats:related-article> ) report the detection of gamma-ray emission from the globular cluster 47 Tucanae, which is coming from an ensemble of millisecond pulsars in the cluster's core. The data imply that there are up to 60 millisecond pulsars in 47 Tucanae, twice as many as predicted by radio observations. In a further companion study, <jats:bold> Abdo <jats:italic>et al.</jats:italic> </jats:bold> (p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" page="848" related-article-type="in-this-issue" vol="325" xlink:href="10.1126/science.1176113">848</jats:related-article> , published online 2 July) searched Fermi Large Area Telescope data for pulsations from all known millisecond pulsars outside of stellar clusters, finding gamma-ray pulsations for eight of them. Their properties resemble those of other gamma-ray pulsars, suggesting that they share the same basic emission mechanism. Indeed, both sets of pulsars favor emission models in which the gamma rays are produced in the outer magnetosphere of the neutron star. </jats:p>

<jats:title>Gamma-Ray Pulsar Bonanza</jats:title> <jats:p> Most of the pulsars we know about were detected through their radio emission; a few are known to pulse gamma rays but were first detected at other wavelengths (see the Perspective by <jats:bold> <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="5942" page="821" related-article-type="in-this-issue" vol="325" xlink:href="10.1126/science.1178573">Halpern</jats:related-article> </jats:bold> ). Using the Fermi Gamma-Ray Space Telescope, <jats:bold> Abdo <jats:italic>et al.</jats:italic> </jats:bold> (p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" page="840" related-article-type="in-this-issue" vol="325" xlink:href="10.1126/science.1175558">840</jats:related-article> , published online 2 July; see the cover) report the detection of 16 previously unknown pulsars based on their gamma-ray emission alone. Thirteen of these coincide with previously unidentified gamma-ray sources, solving the 30-year-old mystery of their identities. Pulsars are fast-rotating neutron stars. With time they slow down and cease to radiate; however, if they are in a binary system, they can have their spin rates increased by mass transfer from their companion stars, starting a new life as millisecond pulsars. In another study, <jats:bold> Abdo <jats:italic>et al.</jats:italic> </jats:bold> (p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" page="845" related-article-type="in-this-issue" vol="325" xlink:href="10.1126/science.1177023">845</jats:related-article> ) report the detection of gamma-ray emission from the globular cluster 47 Tucanae, which is coming from an ensemble of millisecond pulsars in the cluster's core. The data imply that there are up to 60 millisecond pulsars in 47 Tucanae, twice as many as predicted by radio observations. In a further companion study, <jats:bold> Abdo <jats:italic>et al.</jats:italic> </jats:bold> (p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" page="848" related-article-type="in-this-issue" vol="325" xlink:href="10.1126/science.1176113">848</jats:related-article> , published online 2 July) searched Fermi Large Area Telescope data for pulsations from all known millisecond pulsars outside of stellar clusters, finding gamma-ray pulsations for eight of them. Their properties resemble those of other gamma-ray pulsars, suggesting that they share the same basic emission mechanism. Indeed, both sets of pulsars favor emission models in which the gamma rays are produced in the outer magnetosphere of the neutron star. </jats:p>

<jats:title>Porous Anodes for Solid Oxide Fuel Cells</jats:title> <jats:p> Fuel cells that use ion-conducting oxides as the electrolyte can be highly efficient and use hydrocarbon fuels directly. However, their very high operating temperatures (usually above 700°C) can lead to unwanted reactions with their electrode materials and premature degradation of their performance. In order to improve fuel-cell electrochemical performance, <jats:bold> Suzuki <jats:italic>et al.</jats:italic> </jats:bold> (p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" page="852" related-article-type="in-this-issue" vol="325" xlink:href="10.1126/science.1176404">852</jats:related-article> ) describe a route for increasing the porosity of the anode material, which contains nickel oxide and zirconia doped with scandium and cerium and is fabricated as a cylinder. Subsequent coating and firing steps added a layer of a zirconia-based electrolyte and the (La,Sr)(Co,Fe)O <jats:sub>3</jats:sub> cathode. The resulting fuel-cell power density exceeded 1 watt per square centimeter at 600°C, and its performance improved as hydrogen fuel velocities were increased through the cell. </jats:p>

<jats:title>MOFs with Guest Rooms</jats:title> <jats:p> Metal organic framework (MOF) solids typically boast large pores in their crystal lattices that can accommodate molecular guests and are useful as compact media for gas storage. However, guest binding has generally relied upon nonspecific interactions with the framework components. <jats:bold> Li <jats:italic>et al.</jats:italic> </jats:bold> (p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" page="855" related-article-type="in-this-issue" vol="325" xlink:href="10.1126/science.1175441">855</jats:related-article> ) have now prepared MOFs that incorporate macrocyclic ethers into the structural ligands comprising the framework walls within which certain cationic guests can bind quantitatively and site-specifically, akin to the molecular docking of drug molecules within protein receptors. </jats:p>

<jats:title>Friendly Fire</jats:title> <jats:p> Hints of the use of more advanced materials by humans, including symbolic marking and jewelry, appear about 75,000 years ago or so in Africa. <jats:bold> Brown <jats:italic>et al.</jats:italic> </jats:bold> (p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" page="859" related-article-type="in-this-issue" vol="325" xlink:href="10.1126/science.1175028">859</jats:related-article> ; see the Perspective by <jats:bold> <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="5942" page="820" related-article-type="in-this-issue" vol="325" xlink:href="10.1126/science.1178014"> <jats:bold>Webb and Domanski</jats:bold> </jats:related-article> </jats:bold> ) now show that these early modern humans were also experimenting with the use of fire for improved processing of materials. Replication experiments and analysis of artifacts suggest that humans in South Africa at this time, and perhaps earlier, systematically heated stone materials, including silcrete to improve its flaking properties in making tools. </jats:p>

<jats:title>Why Birds of a Feather Flock Together</jats:title> <jats:p> The biological determination of sociality, that is, why one might choose to associate with others and how many, has been unclear. <jats:bold> Goodson <jats:italic>et al.</jats:italic> </jats:bold> (p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" page="862" related-article-type="in-this-issue" vol="325" xlink:href="10.1126/science.1174929">862</jats:related-article> ) show that in gregarious finches, oxytocin-like receptors and their cognate ligand, mesotocin, are associated with group size choices. Receptor distributions clearly differentiate territorial species from flocking species. Furthermore, these compounds appear to play a role in affecting choice in affiliation in mammals, and thus may be conserved across evolutionary distant taxa. </jats:p>

<jats:title>Reducing Sleep Length</jats:title> <jats:p> Humans, like most animals, need their beauty sleep. But the preferred amount and quality of sleep varies between individuals—and some individuals exhibit a heritable, lifetime tendency to sleep less then 6 hours per night. <jats:bold> He <jats:italic>et al.</jats:italic> </jats:bold> (p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" page="866" related-article-type="in-this-issue" vol="325" xlink:href="10.1126/science.1174443">866</jats:related-article> ; see the Perspective by <jats:bold> <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="5942" page="825" related-article-type="in-this-issue" vol="325" xlink:href="10.1126/science.1178713">Hor and Tafti</jats:related-article> </jats:bold> ) identified a mutation in humans associated with people who regularly require shorter than usual sleep duration. The mutation is found in the gene encoding a transcriptional repressor, DEC2, already implicated in regulation of circadian rhythms. Related mutations introduced into mice and flies similarly resulted in shortened sleep phases. </jats:p>