Catálogo de publicaciones - revistas

<jats:p>The genome has spurred interactions between scientists and artists to bring personal voice to this most human of topics</jats:p>

<jats:p>Digital modules for online resources and good metadata help teachers find the museum's rich, authoritative science content to use in their classrooms.</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:p>Understanding the diversification of phenotypes through time—“descent with modification”—has been the focus of evolutionary biology for 150 years. If, contrary to expectations, similarity evolves in unrelated taxa, researchers are guided to uncover the genetic and developmental mechanisms responsible. Similar phenotypes may be retained from common ancestry (homology), but a phylogenetic context may instead reveal that they are independently derived, due to convergence or parallel evolution, or less likely, that they experienced reversal. Such examples of homoplasy present opportunities to discover the foundations of morphological traits. A common underlying mechanism may exist, and components may have been redeployed in a way that produces the “same” phenotype. New, robust phylogenetic hypotheses and molecular, genomic, and developmental techniques enable integrated exploration of the mechanisms by which similarity arises.</jats:p>

<jats:p>The eukaryote maintenance DNA methyltransferase discriminates against de novo CpG methylation sites.</jats:p>

<jats:p>Numerical simulations show that disks around the first stars in the universe were gravitationally unstable and fragmented.</jats:p>

<jats:title>Keeping Time</jats:title> <jats:p> Optical lattice clocks are comprised of atoms placed in an optical lattice formed by opposing laser beams and can be more precise than traditional microwave atomic clocks because of the higher frequency at which they operate, and the number of atoms available for interrogation. However, interactions between the atoms may lead to shifts in the frequency of the clock transition, usually proportional to the atomic density. <jats:bold> Swallows <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="1043" related-article-type="in-this-issue" vol="331" xlink:href="10.1126/science.1196442">1043</jats:related-article> , published online 3 February) demonstrate an opposite and unexpected effect of interactions: For sufficiently strongly interacting systems, the frequency shift is suppressed. Indeed, in a strontium-based fermionic lattice clock, the shift and its associated spread were reduced by an order of magnitude. </jats:p>

<jats:p>Correlation of arrival times of metastable helium atoms is consistent with long-range coherence to higher orders.</jats:p>

<jats:p>A reactive iron compound bound to nitrogen has been isolated in an unusually high oxidation state.</jats:p>

<jats:p> Instead of sulfide or sulfate, the trisulfur ion S <jats:sub>3</jats:sub> <jats:sup>–</jats:sup> is stable at high temperatures. </jats:p>