Catálogo de publicaciones - revistas

<jats:title>Photons from a gravitational wave event</jats:title> <jats:p> Two neutron stars merging together generate a gravitational wave signal and have also been predicted to emit electromagnetic radiation. When the gravitational wave event GW170817 was detected, astronomers rushed to search for the source using conventional telescopes (see the Introduction by Smith). Coulter <jats:italic>et al.</jats:italic> describe how the One-Meter Two-Hemispheres (1M2H) collaboration was the first to locate the electromagnetic source. Drout <jats:italic>et al.</jats:italic> present the 1M2H measurements of its optical and infrared brightness, and Shappee <jats:italic>et al.</jats:italic> report their spectroscopy of the event, which is unlike previously detected astronomical transient sources. Kilpatrick <jats:italic>et al.</jats:italic> show how these observations can be explained by an explosion known as a kilonova, which produces large quantities of heavy elements in nuclear reactions. </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="6370" page="1556" related-article-type="in-this-issue" vol="358" xlink:href="10.1126/science.aap9811">1556</jats:related-article> , p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6370" page="1570" related-article-type="in-this-issue" vol="358" xlink:href="10.1126/science.aaq0049">1570</jats:related-article> , p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6370" page="1574" related-article-type="in-this-issue" vol="358" xlink:href="10.1126/science.aaq0186">1574</jats:related-article> , p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6370" page="1583" related-article-type="in-this-issue" vol="358" xlink:href="10.1126/science.aaq0073">1583</jats:related-article> ; see also p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6370" page="1554" related-article-type="in-this-issue" vol="358" xlink:href="10.1126/science.aar6069">1554</jats:related-article> </jats:p>

<jats:title>Pointing to a second critical point</jats:title> <jats:p> One explanation for the divergence of many of the thermodynamic properties of water is that there is a critical point in deeply supercooled water at some positive pressure. For bulk water samples, these conditions are described as “no man's land,” because ice nucleates before such temperatures can be reached. Kim <jats:italic>et al.</jats:italic> used femtosecond x-ray laser pulses to probe micrometer-sized water droplets cooled to 227 K (see the Perspective by Gallo and Stanley). The temperature dependence of the isothermal compressibility and correlation length extracted from x-ray scattering functions showed maxima at 229 K for H <jats:sub>2</jats:sub> O and 233 K for D <jats:sub>2</jats:sub> O, rather than diverging to infinity. These results point to the existence of the Widom line, a locus of maximum correlation lengths emanating from a critical point in the supercooled regime. </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="6370" page="1589" related-article-type="in-this-issue" vol="358" xlink:href="10.1126/science.aap8269">1589</jats:related-article> ; see also p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6370" page="1543" related-article-type="in-this-issue" vol="358" xlink:href="10.1126/science.aar3575">1543</jats:related-article> </jats:p>

<jats:title>Determining damping of our plates</jats:title> <jats:p> For plate tectonics to operate, a weaker layer called the asthenosphere must underlie the rigid lithospheric plates. Quantifying the difference in strength comes down to how much each layer attenuates energy. Takeuchi <jats:italic>et al.</jats:italic> exploited an ocean-bottom seismic network and seismic energy from the 2011 Japanese Tohoku-oki earthquake to quantify the attenuation in each layer (see the Perspective by Dalton). The attenuation of energy in the asthenosphere lined up with previous estimates, but the lithospheric attenuation was roughly one-fifth as strong as that predicted by some previous models. </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="6370" page="1593" related-article-type="in-this-issue" vol="358" xlink:href="10.1126/science.aao3508">1593</jats:related-article> ; see also p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6370" page="1536" related-article-type="in-this-issue" vol="358" xlink:href="10.1126/science.aar2748">1536</jats:related-article> </jats:p>

<jats:title>Timing a switch in tissue integrity</jats:title> <jats:p> In plants, sperm cells travel through the pollen tube as it grows toward the ovule. Successful fertilization depends on the pollen tube rupturing to release the sperm cells (see the Perspective by Stegmann and Zipfel). Ge <jats:italic>et al.</jats:italic> and Mecchia <jats:italic>et al.</jats:italic> elucidated the intercellular cross-talk that maintains pollen tube integrity during growth but destroys it at just the right moment. The signaling peptides RALF4 and RALF19, derived from the pollen tube, maintain its integrity as it grows. Once in reach of the ovule, a related signaling peptide, RALF34, which derives from female tissues, takes over and causes rupture of the pollen tube. </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="6370" page="1596" related-article-type="in-this-issue" vol="358" xlink:href="10.1126/science.aao3642">1596</jats:related-article> , p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6370" page="1600" related-article-type="in-this-issue" vol="358" xlink:href="10.1126/science.aao5467">1600</jats:related-article> ; see also p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6370" page="1544" related-article-type="in-this-issue" vol="358" xlink:href="10.1126/science.aar4190">1544</jats:related-article> </jats:p>

<jats:title>Timing a switch in tissue integrity</jats:title> <jats:p> In plants, sperm cells travel through the pollen tube as it grows toward the ovule. Successful fertilization depends on the pollen tube rupturing to release the sperm cells (see the Perspective by Stegmann and Zipfel). Ge <jats:italic>et al.</jats:italic> and Mecchia <jats:italic>et al.</jats:italic> elucidated the intercellular cross-talk that maintains pollen tube integrity during growth but destroys it at just the right moment. The signaling peptides RALF4 and RALF19, derived from the pollen tube, maintain its integrity as it grows. Once in reach of the ovule, a related signaling peptide, RALF34, which derives from female tissues, takes over and causes rupture of the pollen tube. </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="6370" page="1596" related-article-type="in-this-issue" vol="358" xlink:href="10.1126/science.aao3642">1596</jats:related-article> , p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6370" page="1600" related-article-type="in-this-issue" vol="358" xlink:href="10.1126/science.aao5467">1600</jats:related-article> ; see also p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6370" page="1544" related-article-type="in-this-issue" vol="358" xlink:href="10.1126/science.aar4190">1544</jats:related-article> </jats:p>

<jats:title>Fungal effectors of wheat stem rust</jats:title> <jats:p> The fungal pathogen Ug99 (named for its identification in Uganda in 1999) threatens wheat crops worldwide. Ug99 can kill entire fields of wheat and is undeterred by many of the disease-resistance genes that otherwise protect wheat crops. Two papers describe two peptides secreted by the fungus as it attacks the wheat (see the Perspective by Moscou and van Esse). Chen <jats:italic>et al.</jats:italic> show that fungal AvrSr50 binds to the plant's immune receptor Sr50, and Salcedo <jats:italic>et al.</jats:italic> show that fungal AvrSr35 binds to Sr35. Successful binding activates the plant's immune defenses. Removing or inactivating these Avr effectors leaves the plant defenseless and susceptible to disease. </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="6370" page="1607" related-article-type="in-this-issue" vol="358" xlink:href="10.1126/science.aao4810">1607</jats:related-article> , p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6370" page="1604" related-article-type="in-this-issue" vol="358" xlink:href="10.1126/science.aao7294">1604</jats:related-article> ; see also p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6370" page="1541" related-article-type="in-this-issue" vol="358" xlink:href="10.1126/science.aar4797">1541</jats:related-article> </jats:p>

<jats:title>Fungal effectors of wheat stem rust</jats:title> <jats:p> The fungal pathogen Ug99 (named for its identification in Uganda in 1999) threatens wheat crops worldwide. Ug99 can kill entire fields of wheat and is undeterred by many of the disease-resistance genes that otherwise protect wheat crops. Two papers describe two peptides secreted by the fungus as it attacks the wheat (see the Perspective by Moscou and van Esse). Chen <jats:italic>et al.</jats:italic> show that fungal AvrSr50 binds to the plant's immune receptor Sr50, and Salcedo <jats:italic>et al.</jats:italic> show that fungal AvrSr35 binds to Sr35. Successful binding activates the plant's immune defenses. Removing or inactivating these Avr effectors leaves the plant defenseless and susceptible to disease. </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="6370" page="1607" related-article-type="in-this-issue" vol="358" xlink:href="10.1126/science.aao4810">1607</jats:related-article> , p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6370" page="1604" related-article-type="in-this-issue" vol="358" xlink:href="10.1126/science.aao7294">1604</jats:related-article> ; see also p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6370" page="1541" related-article-type="in-this-issue" vol="358" xlink:href="10.1126/science.aar4797">1541</jats:related-article> </jats:p>

<jats:title>Warming stresses developing countries</jats:title><jats:p>Weather-induced conflicts in developing countries spill over to developed countries through asylum applications. One approach to estimating the future impacts of climate change is to look at the effects of weather fluctuations. These transient shocks can be interpreted analytically as randomly distributed treatments applied to countries around the world. Missirian and Schlenker analyzed the relation between these localized shocks to agriculture and applications by that country's migrants for asylum in the European Union. When temperatures in the source country deviated from a moderate optimum around 20°C that is best for agriculture, asylum applications increased. Thus, the net forecast is for asylum applications to increase as global temperatures rise.</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="6370" page="1610" related-article-type="in-this-issue" vol="358" xlink:href="10.1126/science.aao0432">1610</jats:related-article></jats:p>

<jats:title>The vascular plants of the Americas</jats:title> <jats:p> Botanical exploration in the Americas has a history that stretches back for half a millennium, with knowledge assembled in diverse regional floras and lists. Ulloa Ulloa <jats:italic>et al.</jats:italic> present a comprehensive and integrated compilation of all known native New World vascular plant species (see the Perspective by Givnish). This compilation, in a publicly available, searchable database, includes 124,993 species—about one-third of the worldwide total. They further present details of the distribution of species across families and genera, the geographical foci of diversity, and the floristic relationships between regions. The rate of plant species discovery in the Americas averages almost 750 annually, so this valuable resource will continue to grow. </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="6370" page="1614" related-article-type="in-this-issue" vol="358" xlink:href="10.1126/science.aao0398">1614</jats:related-article> ; see also p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6370" page="1535" related-article-type="in-this-issue" vol="358" xlink:href="10.1126/science.aar4191">1535</jats:related-article> </jats:p>

<jats:title>Chemical control of transcription</jats:title> <jats:p> Friedreich's ataxia, a devastating neurodegenerative disease with no effective therapy, is caused by an expansion of intronic repeats and hence a reduced expression of the <jats:italic>FXN</jats:italic> gene. Erwin <jats:italic>et al.</jats:italic> synthesized a molecule that specifically targets the expanded repressive repeats. This molecule thereby licenses productive transcription elongation and restores <jats:italic>FXN</jats:italic> expression to normal levels. In the future, similar interventions may be effective in a diverse array of diseases caused by unstable expansions in microsatellite repeats. </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="6370" page="1617" related-article-type="in-this-issue" vol="358" xlink:href="10.1126/science.aan6414">1617</jats:related-article> </jats:p>