Catálogo de publicaciones - revistas

<jats:p>Randomized controlled trials explore how to improve human adoption of promising technologies.</jats:p>

<jats:p>Multiscale models integrating social, economic, and environmental aspects are critical for evaluating proposed policies.</jats:p>

<jats:title>Environmental Determinism?</jats:title> <jats:p> Earth's millions of species influence a wide range of environmental processes, including elemental cycling, the stability of ecosystems, and the goods and services they provide. <jats:bold> Naeem <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="1401" related-article-type="in-this-issue" vol="336" xlink:href="10.1126/science.1215855">1401</jats:related-article> ) review recent advances in the young and evolving field of biodiversity and ecosystem functioning, explore the extent to which the field is becoming a predictive science, and indicate how the field needs to develop in order to aid worldwide efforts to achieve environmental sustainability in the face of rising rates of extinction. </jats:p>

<jats:p>In midsummer, diatoms have taken advantage of thinning ice cover to feed in nutrient-rich waters.</jats:p>

<jats:title>Dating Cave Paintings</jats:title> <jats:p> A number of caves in Europe contain exquisite ancient art. Most of the art has been thought to be produced during the time of last glaciation by recently arrived modern humans, but dating of the art has been problematic because the art contains only minimal amounts of carbon for radiocarbon dating. <jats:bold> Pike <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="1409" related-article-type="in-this-issue" vol="336" xlink:href="10.1126/science.1219957">1409</jats:related-article> ; see the cover; see the Perspective by <jats:bold> <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6087" page="1387" related-article-type="in-this-issue" vol="336" xlink:href="10.1126/science.1224185">Hellstrom</jats:related-article> </jats:bold> ) have now obtained U-series dates on the calcite crusts that formed over the art from 11 caves in northwestern Spain. The ages from three caves are older than 35,000 years ago, and one dates to nearly 41,000 years ago. The earliest art used primarily red and was relatively formless; animal depictions appeared later. This dating is near the time of the arrival of modern humans and, because Neandertals were also present, complicates identifying the artists. </jats:p>

<jats:title>Spin Recovery</jats:title> <jats:p> Spin-orbit interactions present in many semiconductors are used to manipulate the spin of an electron in spin-based electronics. However, this same interaction is also responsible for the loss of information contained in a spin when it changes its direction during the scattering off of impurities. <jats:bold>Sugimoto and Nagaosa</jats:bold> (p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" page="1413" related-article-type="in-this-issue" vol="336" xlink:href="10.1126/science.1217346">1413</jats:related-article> ) describe a new quantity, twisted spin, which, unlike regular spin, survives the scatterings; moreover, because the spin-orbit interaction is turned off adiabatically, the lost spin information is retrieved. </jats:p>

<jats:title>Dropping a Dimension?</jats:title> <jats:p> In most magnetic materials, the exchange interaction causes the spins on the neighboring sites of a crystal lattice to align. In the absence of exchange interactions, dipolar interactions, which are highly orientation dependent, are also expected to be able to cause magnetism. <jats:bold> Kraemer <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="1416" related-article-type="in-this-issue" vol="336" xlink:href="10.1126/science.1221878">1416</jats:related-article> ) present evidence for antiferromagnetism in a dipolar-coupled material, LiErF <jats:sub>4</jats:sub> . Although a three-dimensional system, its critical behavior was more reminiscent of a two-dimensional material. </jats:p>

<jats:title>B-B Bond</jats:title> <jats:p> Alkynes contain carbon-carbon triple bonds and represent a diverse class of organic compounds. In principle, valence rules suggest that the boron analog of an alkyne, with a B-B triple bond, ought to be accessible by appending a two-electron donor to each B atom. <jats:bold> Braunschweig <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="1420" related-article-type="in-this-issue" vol="336" xlink:href="10.1126/science.1221138">1420</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="6087" page="1394" related-article-type="in-this-issue" vol="336" xlink:href="10.1126/science.1224003">Frenking and Holzmann</jats:related-article> </jats:bold> ) now present the synthesis, isolation, and crystallization of a solid, triple-bonded diboryne, with N-heterocyclic carbenes as the terminal substituents, which contains the expected linear bonding geometry. </jats:p>

<jats:title>Porous Blocks</jats:title> <jats:p> Porous materials are widely used in separation processes and catalysis. <jats:bold>Seo and Hillmyer</jats:bold> (p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" page="1422" related-article-type="in-this-issue" vol="336" xlink:href="10.1126/science.1221383">1422</jats:related-article> ) used block copolymers that naturally separate into domains to achieve a continuous network of pores. A chain transfer agent was used to direct the copolymerization of the two materials in situ to generate a structure with a percolating porous structure with pore sizes of a few nanometers and with tunable control over the polymer properties and extent of cross-linking. </jats:p>

<jats:title>The Rocks That Hit the Moon</jats:title> <jats:p> The cratered surface of the Moon bears witness to the numerous impacts it has suffered. Chemical signatures of these impacts have been detected indirectly. Now, <jats:bold> Joy <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="1426" related-article-type="in-this-issue" vol="336" xlink:href="10.1126/science.1219633">1426</jats:related-article> , published online 17 May; see the Perspective by <jats:bold> <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6087" page="1390" related-article-type="in-this-issue" vol="336" xlink:href="10.1126/science.1224184">Rubin</jats:related-article> </jats:bold> ) report the detection and characterization of meteorite fragments preserved in ancient lunar regolith breccias from the Apollo 16 landing site. These meteoritic fragments represent direct samples of the population of small bodies traversing the inner solar system at around 3.4 billion years ago—the same time or just after the basin-forming epoch on the Moon. </jats:p>