Catálogo de publicaciones - revistas

<jats:p>The identification of large numbers of human embryonic stem cell enhancers provides a useful tool to study cell fate and disease.</jats:p>

<jats:p>Designing systems from nano- to macroscale can optimize the synergistic integration of sustainable energy and waste treatment in buildings.</jats:p>

<jats:title>Accretion Analog</jats:title> <jats:p> Mass flow from a circumstellar disk onto a young star's surface plays an important role in the final stages of star formation but the details of this complex process are not well understood. <jats:bold> Reale <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="6143" page="251" related-article-type="in-this-issue" vol="341" xlink:href="10.1126/science.1235692">251</jats:related-article> , published online 20 June) analyzed a solar flare that led to bright impacts of plasma onto the solar surface. Numerical simulations suggest that these events can be seen as analogs to accretion of matter onto stars and can thus be used to understand stellar accretion. </jats:p>

<jats:title>Magnetic Self-Assembly</jats:title> <jats:p> During self-assembly, objects spontaneously assemble into larger ordered patterns as observed, for example, in the phase segregation of block copolymers or the assembly of micrometer-sized objects and components in electronics. In dynamic self-assembly, the ordered patterns require an external energy source, but still form because of intrinsic interactions within the system. <jats:bold> Timonen <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="6143" page="253" related-article-type="in-this-issue" vol="341" xlink:href="10.1126/science.1233775">253</jats:related-article> ; see the Perspective by <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6143" page="243" related-article-type="in-this-issue" vol="341" xlink:href="10.1126/science.1241793"> <jats:bold> Hermans <jats:italic>et al.</jats:italic> </jats:bold> </jats:related-article> ) studied the organization of magnetic droplets, in the form of a ferrofluid, placed on a low-friction surface. A time-varying magnetic field transformed the statically arranged droplets into a dynamic pattern. </jats:p>

<jats:title>More Magnetoresistance</jats:title> <jats:p> When data is read off your computer's hard drive, chances are that the read head is using the phenomenon of magnetoresistance (MR)—the dependence of electrical resistance on applied magnetic field—to interpret the magnetic signature of the data on the disk. Devices that have the large MR necessary for such tasks are usually made of layers of magnetic materials. <jats:bold> Mahato <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="6143" page="257" related-article-type="in-this-issue" vol="341" xlink:href="10.1126/science.1237242">257</jats:related-article> , published online 4 July) observed a large MR effect in a nonmagnetic material—organic molecules squeezed into a zeolite crystal. Importantly for potential future applications, the effect was observed at room temperature and at low magnetic fields. </jats:p>

<jats:title>Mars' Atmosphere from Curiosity</jats:title> <jats:p> The Sample Analysis at Mars (SAM) instrument on the Curiosity rover that landed on Mars in August last year is designed to study the chemical and isotopic composition of the martian atmosphere. <jats:bold> Mahaffy <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="6143" page="263" related-article-type="in-this-issue" vol="341" xlink:href="10.1126/science.1237966">263</jats:related-article> ) present volume-mixing ratios of Mars' five major atmospheric constituents (CO <jats:sub>2</jats:sub> , Ar, N <jats:sub>2</jats:sub> , O <jats:sub>2</jats:sub> , and CO) and isotope measurements of <jats:sup>40</jats:sup> Ar/ <jats:sup>36</jats:sup> Ar and C and O in CO <jats:sub>2</jats:sub> , based on data from one of SAM's instruments, obtained between 31 August and 21 November 2012. <jats:bold> Webster <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="6143" page="260" related-article-type="in-this-issue" vol="341" xlink:href="10.1126/science.1237961">260</jats:related-article> ) used data from another of SAM's instruments obtained around the same period to determine isotope ratios of H, C, and O in atmospheric CO <jats:sub>2</jats:sub> and H <jats:sub>2</jats:sub> O. Agreement between the isotopic ratios measured by SAM with those of martian meteorites, measured in laboratories on Earth, confirms the origin of these meteorites and implies that the current atmospheric reservoirs of CO <jats:sub>2</jats:sub> and H <jats:sub>2</jats:sub> O were largely established after the period of early atmospheric loss some 4 billion years ago. </jats:p>

<jats:title>Mars' Atmosphere from Curiosity</jats:title> <jats:p> The Sample Analysis at Mars (SAM) instrument on the Curiosity rover that landed on Mars in August last year is designed to study the chemical and isotopic composition of the martian atmosphere. <jats:bold> Mahaffy <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="6143" page="263" related-article-type="in-this-issue" vol="341" xlink:href="10.1126/science.1237966">263</jats:related-article> ) present volume-mixing ratios of Mars' five major atmospheric constituents (CO <jats:sub>2</jats:sub> , Ar, N <jats:sub>2</jats:sub> , O <jats:sub>2</jats:sub> , and CO) and isotope measurements of <jats:sup>40</jats:sup> Ar/ <jats:sup>36</jats:sup> Ar and C and O in CO <jats:sub>2</jats:sub> , based on data from one of SAM's instruments, obtained between 31 August and 21 November 2012. <jats:bold> Webster <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="6143" page="260" related-article-type="in-this-issue" vol="341" xlink:href="10.1126/science.1237961">260</jats:related-article> ) used data from another of SAM's instruments obtained around the same period to determine isotope ratios of H, C, and O in atmospheric CO <jats:sub>2</jats:sub> and H <jats:sub>2</jats:sub> O. Agreement between the isotopic ratios measured by SAM with those of martian meteorites, measured in laboratories on Earth, confirms the origin of these meteorites and implies that the current atmospheric reservoirs of CO <jats:sub>2</jats:sub> and H <jats:sub>2</jats:sub> O were largely established after the period of early atmospheric loss some 4 billion years ago. </jats:p>

<jats:title>Major Meltdown</jats:title> <jats:p> The ice shelves and floating ice tongues that surround Antarctica cover more than 1.5 million square kilometers—approximately the size of the entire Greenland Ice Sheet. Conventional wisdom has held that ice shelves around Antarctica lose mass mostly by iceberg calving, but recently it has become increasingly clear that melting by a warming ocean may also be important. <jats:bold> Rignot <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="6143" page="266" related-article-type="in-this-issue" vol="341" xlink:href="10.1126/science.1235798">266</jats:related-article> , published 13 June) present detailed glaciological estimates of ice-shelf melting around the entire continent of Antarctica, which show that basal melting accounts for as much mass loss as does calving. </jats:p>

<jats:title>Ancient Warriors or Murderers?</jats:title><jats:p>Some have suggested that the human predilection for war is ancient, perhaps dating back to the emergence of our species, while others maintain that evidence for such early warring is scant. Past studies that looked at nomadic foraging bands as models of early humans and their potential for conflict concluded that war is in our blood.<jats:bold>Fry and Söderberg</jats:bold>(p.<jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6143" page="270" related-article-type="in-this-issue" vol="341" xlink:href="10.1126/science.1235675">270</jats:related-article>), however, reexamined the standard cross-cultural sample, the main repository for behavioral data on forage bands, and found little evidence for large-scale conflicts or wars. Instead, the majority of incidences of lethal aggression in these societies were homicides driven by a variety of factors relevant at the individual or family scale.</jats:p>

<jats:title>Romancing the Frog</jats:title> <jats:p> In túngara frogs, auditory and visual components of mate calling do not naturally occur together. <jats:bold>Taylor and Ryan</jats:bold> (p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6143" page="273" related-article-type="in-this-issue" vol="341" xlink:href="10.1126/science.1237113">273</jats:related-article> , published online 6 June) now show that two signals that are unattractive to female frogs when presented alone become highly attractive when presented together. In a kind of “perceptual rescue,” the unique combination of two signals increased the receiver's interest in the previously uninteresting signals. </jats:p>