Catálogo de publicaciones - revistas

<jats:p>New research on tropical beetles could help narrow estimates of how many species live on Earth.</jats:p>

<jats:p>A new model for free electrons in water suggests that they are localized in regions of enhanced rather than depleted water density.</jats:p>

<jats:p>The repressive activity of a transcription factor allows thymocytes to shed alternative cell fates and become T cells.</jats:p>

<jats:p>Precision measurements of chemical processes are providing a clearer picture of how the universe evolved.</jats:p>

<jats:title>Blissful Ignorance?</jats:title> <jats:p> Although recent research has established the remarkable ways in which cognitive processing can occur without our being aware of it—for instance, casual exposure to retiree-related words, such as “elderly,” induces us to walk more slowly—behavior that is directed toward goals still seems to be the product of conscious thought. <jats:bold>Custers and Aarts</jats:bold> (p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" page="47" related-article-type="in-this-issue" vol="329" xlink:href="10.1126/science.1188595">47</jats:related-article> ) review a set of findings that point toward the possibility that goals may, in fact, also be vulnerable to manipulation via avenues of which we remain blissfully unaware. They place these results within a framework that reveals how thoroughly unconscious processes permeate our everyday activities. </jats:p>

<jats:p>Ancient carbonaceous material possibly delivered during meteorite bombardment has been found in lunar rock.</jats:p>

<jats:title>Let There Be Life</jats:title> <jats:p> The DNA sequence information from thousands of genomes is stored digitally as ones and zeros in computer memory. Now, <jats:bold> Gibson <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="52" related-article-type="in-this-issue" vol="329" xlink:href="10.1126/science.1190719">52</jats:related-article> , published online 20 May; see the cover; see the Policy Forum by <jats:bold> <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="5987" page="38" related-article-type="in-this-issue" vol="329" xlink:href="10.1126/science.1193749">Cho and Relman</jats:related-article> </jats:bold> ) have brought together technologies from the past 15 years to start from digital information on the genome of <jats:italic>Mycoplasma mycoides</jats:italic> to chemically synthesize the genomic DNA as segments that could then be assembled in yeast and transplanted into the cytoplasm of another organism. A number of methods were also incorporated to facilitate testing and error correction of the synthetic genome segments. The transplanted genome became established in the recipient cell, replacing the recipient genome, which was lost from the cell. The reconstituted cells were able to replicate and form colonies, providing a proof-of-principle for future developments in synthetic biology. </jats:p>

<jats:title>Planet Is Born</jats:title> <jats:p> The 10-million-year-old star β Pictoris, has long been suspected to host a planet. Through images obtained with the Very Large Telescope, an array of four telescopes located in Chile, <jats:bold> Lagrange <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="57" related-article-type="in-this-issue" vol="329" xlink:href="10.1126/science.1187187">57</jats:related-article> , published online 10 June) now confirm the presence of a young, giant planet, β Pictoris b, orbiting within the dusty disk that surrounds the star. β Pictoris b orbits closer to its star than Uranus and Neptune do to the Sun in our solar system. This orbital separation is consistent with the in situ formation of the planet via a core accretion mechanism. Thus, giant planets can form within a stellar dust disk in only a few million years. </jats:p>

<jats:title>Maintaining the Supercurrent</jats:title> <jats:p> When a superconductor is placed in contact with a ferromagnet, the antiparallel spin pairs that form the supercurrent are expected to be broken almost immediately upon entering the ferromagnet, which tends to orient spins parallel to each other. If the supercurrent survives for more than a few nanometers, it is assumed that a change of pairing symmetry has taken place, with the spin-singlet pairs having been converted into spin-triplets. Magnetic inhomogeneity at the superconductor-ferromagnet interface is thought to account for this change. <jats:bold> Robinson <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="59" related-article-type="in-this-issue" vol="329" xlink:href="10.1126/science.1189246">59</jats:related-article> , published online 10 June) have now been able to observe long-ranged supercurrents in a symmetric junction consisting of a superconductor, a conical magnet, and a ferromagnet. The conical magnet layer provided the required inhomogeneity, and varying its thickness enabled control over the magnitude of the current. </jats:p>

<jats:title>Quantum Anomalous Hall Effect</jats:title> <jats:p> In addition to the Hall effect, which appears as a voltage change in conductors in response to an external magnetic field, ferromagnets exhibit the anomalous Hall effect, which is often proportional to their magnetization and independent of the presence of the magnetic field. This effect, first observed more than a century ago, has not been realized in its quantized form. <jats:bold> Yu <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="61" related-article-type="in-this-issue" vol="329" xlink:href="10.1126/science.1187485">61</jats:related-article> , published online 3 June) propose a realization of a quantum anomalous Hall system by magnetically doping thin films of three-dimensional topological insulators and calculate the effects of various dopants and film thicknesses. The resulting insulators are predicted to have long-range ferromagnetic order, potentially joining dilute magnetic semiconductors as candidates for spintronic applications. </jats:p>