Catálogo de publicaciones - revistas

<jats:p>A similar approach to analyze protein trafficking arrives at two opposing models of movement through the cell's secretory pathway.</jats:p>

<jats:p>The Genetic Engineering Proposal Project, an IBI prize-winning module, teaches biology students to devise innovative bioproducts or solutions to environmental or health 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>Observing Earth's Magnetotail</jats:title> <jats:p> Magnetic reconnection is a process that converts magnetic energy to kinetic energy, thermal energy, and particle acceleration. The process operates in Earth's magnetotail, the narrow and elongated region of the magnetosphere that extends away from the Sun, and is believed to power Earth's auroras and other space physics phenomena. <jats:bold> Angelopoulos <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="6153" page="1478" related-article-type="in-this-issue" vol="341" xlink:href="10.1126/science.1236992">1478</jats:related-article> ) present an observational study of energy conversion in the magnetotail and the associated transport of magnetic flux during a geomagnetic substorm. </jats:p>

<jats:title>Diurnal Immunology</jats:title> <jats:p> Like most organ systems in the body, several components of the immune system appear to be regulated in a diurnal manner. However, the cell populations affected, the underlying molecular mechanisms controlling these processes, and the functional consequences of such regulation are poorly understood. Now, <jats:bold> Nguyen <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="6153" page="1483" related-article-type="in-this-issue" vol="341" xlink:href="10.1126/science.1240636">1483</jats:related-article> , published online 22 August; see the Perspective by <jats:related-article issue="6153" page="" related-article-type="in-this-issue" vol="341"> <jats:bold>Druzd and Scheiermann</jats:bold> </jats:related-article> ) have found that trafficking of monocytes to sites of inflammation is regulated in a diurnal manner in mice. Mice harboring a myeloid cell-specific deletion in the clock protein, BMAL1, showed reduced fitness in response to both acute and chronic inflammation. </jats:p>

<jats:title>Finally Out</jats:title> <jats:p> Last summer, it was not clear if the Voyager 1 spacecraft had finally crossed the heliopause—the boundary between the heliosphere and interstellar space. <jats:bold> Gurnett <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="6153" page="1489" related-article-type="in-this-issue" vol="341" xlink:href="10.1126/science.1241681">1489</jats:related-article> , published online 12 September) present results from the Plasma Wave instrument on Voyager 1 that provide evidence that the spacecraft was in the interstellar plasma during two periods, October to November 2012 and April to May 2013, and very likely in the interstellar plasma continuously since the series of boundary crossings that occurred in July to August 2012. </jats:p>

<jats:title>Assessing Brown Dwarfs</jats:title> <jats:p> The last 2 years have seen the detection of dozens of very cold brown dwarfs. At temperatures around 300 to 500 kelvin, brown dwarfs are expected to have masses comparable to those of gas-giant planets, but because their distances are unknown, it has not been possible to estimate their masses. <jats:bold>Dupuy and Kraus</jats:bold> (p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6153" page="1492" related-article-type="in-this-issue" vol="341" xlink:href="10.1126/science.1241917">1492</jats:related-article> , published online 5 September) used data from the Spitzer Space Telescope to measure accurate distances to very cold brown dwarfs, which allowed them to determine the dwarfs' luminosities, temperatures, and masses. The results strengthen the connection between the coolest brown dwarfs and gas-giant exoplanets. </jats:p>

<jats:title>Half-Massless</jats:title> <jats:p> Certain materials, such as topological crystalline insulators (TCIs), host robust surface states that have a Dirac (graphene-like) dispersion associated with massless carriers; the breaking of protective symmetry within such materials should cause the carriers to acquire mass. <jats:bold> Okada <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="6153" page="1496" related-article-type="in-this-issue" vol="341" xlink:href="10.1126/science.1239451">1496</jats:related-article> , published online 29 August) used scanning tunneling microscopy to map out the energies of the electronic levels of the TCI Pb <jats:sub> 1- <jats:italic>x</jats:italic> </jats:sub> Sn <jats:sub> <jats:italic>x</jats:italic> </jats:sub> Se as a function of the strength of an external magnetic field. The massless Dirac fermions coexisted with massive ones, presumably as a consequence of a distortion of the crystalline structure affecting only one of the two mirror symmetries. </jats:p>

<jats:title>Making the Grain</jats:title> <jats:p> Most metals contain a large number of ordered crystalline regions that are separated by disordered grain boundaries. If the material is annealed at elevated temperatures, the larger grains will grow uniformly at the expense of the smaller ones. This process slows down over time, making it hard to create very large grains. Abnormal grain growth, in which a few of the crystalline regions grow much faster and larger than the others, can occur if the material is put through a complex annealing process involving straining of the samples. <jats:bold> Omori <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="6153" page="1500" related-article-type="in-this-issue" vol="341" xlink:href="10.1126/science.1238017">1500</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="6153" page="1461" related-article-type="in-this-issue" vol="341" xlink:href="10.1126/science.1245056">Taleff and Pedrazas</jats:related-article> </jats:bold> ) find that a much simpler and shorter annealing process can trigger abnormal grain growth in copper-based shape-memory alloys. Thermal cycling between a high-temperature single-phase region and a lower-temperature two-phase region generated dislocations at low temperatures and grain growth on heating. Because this method does not require external straining of the sample, it is not limited to thin sheets or wires. </jats:p>