Catálogo de publicaciones - revistas

<jats:p>Carbon dioxide emissions cuts implemented today would affect the rate of future global warming immediately.</jats:p>

<jats:p>A class of circular RNAs that regulates microRNAs is abundant in mammalian cells.</jats:p>

<jats:p>Heating of gold nanoparticles by radio-frequency waves, which is of interest for clinical applications, can occur if the nanoparticles are made magnetic.</jats:p>

<jats:p> Studies of melting iron at extreme temperature and pressure provide a better understanding of the temperature of Earth's core. <jats:named-content content-type="related-content"> [Also see Report by <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6131" page="464" related-article-type="in-this-issue" vol="340" xlink:href="10.1126/science.1233514"> Anzellini <jats:italic>et al.</jats:italic> </jats:related-article> ] </jats:named-content> </jats:p>

<jats:p>Root Cause Analysis, an IBI prize–winning module, requires students to use a systematic approach to analyze complex problems.</jats:p>

<jats:p> A monthly roundup of recent news and projects of <jats:italic>Science</jats:italic> 's publisher, the American Association for the Advancement of Science. </jats:p>

<jats:title>Daylight Determines Dopamine</jats:title> <jats:p> Expression of the appropriate neurotransmitters is essential for the function of neural circuits. Can neurons change their transmitter phenotype to deal with alterations in the environment? <jats:bold> Dulcis <jats:italic>et al.</jats:italic> </jats:bold> (p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6131" page="449" related-article-type="in-this-issue" vol="340" xlink:href="10.1126/science.1234152">449</jats:related-article> ; see the Perspective by <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6131" page="436" related-article-type="in-this-issue" vol="340" xlink:href="10.1126/science.1238518"> <jats:bold>Birren and Marder</jats:bold> </jats:related-article> ) exposed adult rats to different photoperiods mimicking summer and winter daylengths. Neurotransmitter expression switched between dopamine and somatostatin in hypothalamic neurons that regulate release of corticotropin-releasing factor. Transmitter switching occurred at the transcriptional level and was accompanied by changes in postsynaptic receptors. </jats:p>

<jats:title>Double Vision</jats:title> <jats:p> Vaterite is the least stable form of anhydrous crystalline calcium carbonate. While rarely found in geological contexts, it is an important biological precursor and occurs as a minor component in the shells of some organisms. The crystal structure of vaterite has long been debated with no model able to explain all the experimentally observed diffraction spots. <jats:bold> Kabalah-Amitai <jats:italic>et al.</jats:italic> </jats:bold> (p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6131" page="454" related-article-type="in-this-issue" vol="340" xlink:href="10.1126/science.1232139">454</jats:related-article> ) show that vaterite contains two coexisting crystallographic structures that form a pseudo-single crystal. </jats:p>

<jats:title>How Copper Clicks</jats:title> <jats:p> The copper-catalyzed coupling of azides and alkynes has been termed a “click” reaction on account of its efficiency and versatility, but despite its widespread use, the mechanism remains somewhat unclear. Through a series of kinetic and isotopic labeling studies, <jats:bold> Worrell <jats:italic>et al.</jats:italic> </jats:bold> (p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6131" page="457" related-article-type="in-this-issue" vol="340" xlink:href="10.1126/science.1229506">457</jats:related-article> , published online 4 April) show that, in the case of terminal alkynes (capped at one end by an H atom), two equivalents of copper participate in activating each molecule's reactivity toward azide. Surprisingly, the reaction also appears to proceed through an intermediate in which the two copper centers become equivalent and functionally exchangeable, despite initially coordinating to distinct sites on the alkyne. </jats:p>

<jats:title>Saturn's Meteoroid Crash</jats:title> <jats:p> During Saturn's equinox in 2009, when the Sun illuminated its rings edge-on, images taken by the Cassini spacecraft showed dust clouds appearing as bright streaks above the rings. Similar streaks were detected in 2005 and 2012 when Cassini observed the C ring at close range. <jats:bold> Tiscareno <jats:italic>et al.</jats:italic> </jats:bold> (p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6131" page="460" related-article-type="in-this-issue" vol="340" xlink:href="10.1126/science.1233524">460</jats:related-article> ) suggest that the cause of each observed feature is likely to be the impact of a stream of recently disrupted material originating from a meteoroid impact onto the ring and derive the influx rate of meteoroids at Saturn. </jats:p>