Catálogo de publicaciones - revistas

<jats:title>An electronic wedding cake</jats:title> <jats:p> In nanostructures such as quantum dots, spatial confinement forces electrons to assume discrete energy levels. Quantization can also occur in an external magnetic field, where electrons' energies group into so-called Landau levels (LLs). Gutiérrez <jats:italic>et al.</jats:italic> explored the interplay between these two mechanisms and electronic interactions in a circulator resonator made of graphene. As an external magnetic field was increased, the electron quantum states transformed from atomic-like states to LL-like states. Electronic interactions caused a characteristic wedding cake–like shape of electronic density at high fields. </jats:p> <jats:p> <jats:italic>Science</jats:italic> , this issue p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6404" page="789" related-article-type="in-this-issue" vol="361" xlink:href="10.1126/science.aar2014">789</jats:related-article> </jats:p>

<jats:title>Cooperative quantum magnetism</jats:title> <jats:p> One of the earliest and most intensively studied problems in quantum optics is the interaction of a two-level system (an atom) with a single photon. This simple system provides a rich platform for exploring exotic light-matter interactions and the emergence of more complex phenomena such as superradiance, which is a cooperative effect that emerges when the density of atoms is increased and coupling between them is enhanced. Going beyond the light-matter system, Li <jats:italic>et al.</jats:italic> observed analogous cooperative effects for coupled magnetic systems. The results suggest that ideas in quantum optics could be carried over and used to control and predict exotic phases in condensed matter systems. </jats:p> <jats:p> <jats:italic>Science</jats:italic> , this issue p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6404" page="794" related-article-type="in-this-issue" vol="361" xlink:href="10.1126/science.aat5162">794</jats:related-article> </jats:p>

<jats:title>Mercury sinking</jats:title> <jats:p> Mercury is a highly toxic, globally ubiquitous pollutant that can seriously damage human health. Most mercury pollution enters the atmosphere from burning coal and other fossil fuels and from industrial activity, but where does it all go? Zaferani <jats:italic>et al.</jats:italic> analyzed biogenic siliceous sediments (diatom ooze) from off the coast of Antarctica and found that they contained surprisingly large amounts of mercury. The results suggest that as much as 25% of mercury emissions over the past 150 years could be trapped in sediments like these, revealing the important role that the marine biological pump may play in the global mercury cycle. </jats:p> <jats:p> <jats:italic>Science</jats:italic> , this issue p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6404" page="797" related-article-type="in-this-issue" vol="361" xlink:href="10.1126/science.aat2735">797</jats:related-article> </jats:p>

<jats:title>Hidden truths of enteroviruses</jats:title> <jats:p>Enteroviruses are important drivers of global health, but few countries undertake enterovirus surveillance. Pons-Salort and Grassly used Japanese surveillance data to model the interplay between the ratio of susceptible and immune individuals, accounting for declining birth and death rates, incomplete surveillance, and seasonality of infection (see the Perspective by Nikolay and Cauchemez). Enteroviruses have highly predictable yet highly nonlinear dynamics. The model also reveals signatures of increased pathogenicity and of antigenic change and transmissibility.</jats:p> <jats:p> <jats:italic>Science</jats:italic> , this issue p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6404" page="800" related-article-type="in-this-issue" vol="361" xlink:href="10.1126/science.aat6777">800</jats:related-article> ; see also p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6404" page="755" related-article-type="in-this-issue" vol="361" xlink:href="10.1126/science.aau6932">755</jats:related-article> </jats:p>

<jats:title>Fishin' gone?</jats:title> <jats:p> Because gas solubility decreases as temperatures increase, global warming is likely to cause oxygen loss from the oceans. This could have a detrimental impact on fish populations, the fishing industry, and global food availability. Have such impacts occurred before? Yao <jats:italic>et al.</jats:italic> report sulfur isotopic data from the Paleocene-Eocene Thermal Maximum, an interval around 55 million years ago when atmospheric carbon dioxide concentrations and global temperatures were also high. They found widespread anoxia and resulting high concentrations of hydrogen sulfide, which is toxic to marine organisms. Similar effects could have severe negative effects on ocean ecosystems. </jats:p> <jats:p> <jats:italic>Science</jats:italic> , this issue p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6404" page="804" related-article-type="in-this-issue" vol="361" xlink:href="10.1126/science.aar8658">804</jats:related-article> </jats:p>

<jats:title>An additional cell cycle checkpoint</jats:title> <jats:p> Cell division is controlled by checkpoints that regulate the temporal order of the cell cycle phases, including the G <jats:sub>1</jats:sub> /S, G <jats:sub>2</jats:sub> /M, and metaphase/anaphase transitions. Yet there are no known control mechanisms for a fourth fundamental transition—the S/G <jats:sub>2</jats:sub> transition. Saldivar <jats:italic>et al.</jats:italic> report a switchlike control mechanism that regulates the S/G <jats:sub>2</jats:sub> transition. The checkpoint kinase ATR senses ongoing DNA replication in S phase and represses the mitotic transcriptional network, ensuring that DNA replication in S phase is completed before mitosis. </jats:p> <jats:p> <jats:italic>Science</jats:italic> , this issue p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6404" page="806" related-article-type="in-this-issue" vol="361" xlink:href="10.1126/science.aap9346">806</jats:related-article> </jats:p>

<jats:title>Humans as models of human disease</jats:title> <jats:p> Mice are a convenient model for exploring the functions of cellular signaling pathways. Occasionally, however, an “experiment of nature” highlights the perils of overreliance on mice. RIPK1 is a well studied protein kinase that regulates cell death. Mice deficient in RIPK1 die soon after birth because of the protein's widespread role in multiple tissues and organs. Cuchet-Lourenço <jats:italic>et al.</jats:italic> studied patients with inherited immunodeficiency of unknown cause (see the Perspective by Pasparakis and Kelliher). They identified inactivating mutations in the <jats:italic>RIPK1</jats:italic> gene in four individuals. Unlike what has been seen in mice, the deleterious effects of RIPK1 loss in humans were confined to the immune system, a finding with potential therapeutic implications. </jats:p> <jats:p> <jats:italic>Science</jats:italic> , this issue p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6404" page="810" related-article-type="in-this-issue" vol="361" xlink:href="10.1126/science.aar2641">810</jats:related-article> ; see also p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6404" page="756" related-article-type="in-this-issue" vol="361" xlink:href="10.1126/science.aau6962">756</jats:related-article> </jats:p>

<jats:p>A weekly roundup of information on newly offered instrumentation, apparatus, and laboratory materials of potential interest to researchers.</jats:p>