Catálogo de publicaciones - revistas

<jats:title>Clocking electrons as they exit a metal</jats:title> <jats:p> Einstein earned his Nobel Prize for a quantum-mechanical explanation of electron ejection from metals by light. More than a century later, attosecond spectroscopy has let researchers explore that process in real time. Tao <jats:italic>et al.</jats:italic> used attosecond pulse trains to distinguish the dynamics of electrons excited from a nickel surface into discrete states versus free space (see the Perspective by Bovensiepen and Liggues). They succeeded in resolving a time delay of ∼200 as that was associated with excitation into unoccupied band states. </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="6294" page="62" related-article-type="in-this-issue" vol="353" xlink:href="10.1126/science.aaf6793">62</jats:related-article> ; see also p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6294" page="28" related-article-type="in-this-issue" vol="353" xlink:href="10.1126/science.aag1090">28</jats:related-article> </jats:p>

<jats:title>Female-fatal product of the Yob gene</jats:title> <jats:p> Mechanisms of sex determination are highly variable and complex in invertebrates. For vector-borne disease control strategies, it is important to understand the reproductive biology of the organisms involved. Krzywinska <jats:italic>et al.</jats:italic> have studied sex determination in species of <jats:italic>Anopheles</jats:italic> mosquitoes, whose females suck blood and can transmit malaria parasites (see the Perspective by Sinkins). One gene called <jats:italic>Yob</jats:italic> is found only on the Y chromosome of males. <jats:italic>Yob</jats:italic> is expressed in male embryos within 2 hours of eggs being laid, and transcription continues lifelong. If <jats:italic>Yob</jats:italic> is injected into embryos younger than 2 hours, only male mosquitoes emerge, because <jats:italic>Yob</jats:italic> 's presence is lethal to female embryos. </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="6294" page="67" related-article-type="in-this-issue" vol="353" xlink:href="10.1126/science.aaf5605">67</jats:related-article> ; see also p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6294" page="33" related-article-type="in-this-issue" vol="353" xlink:href="10.1126/science.aag1012">33</jats:related-article> </jats:p>

<jats:title>Changing sex ratios</jats:title> <jats:p> Climate-warming temperatures might be expected to affect the sex ratio of species if sex determination is temperature-dependent. Petry <jats:italic>et al.</jats:italic> show that indirect climate effects could also alter sex ratios in species in which sex is genetically determined and damage reproductive fitness (see the Perspective by Etterson and Mazer). Over four decades, sex ratios in populations of a dioecious alpine plant have shifted toward females as a result of the different water needs of the male and female plants. The lack of males has reduced the reproductive success and fitness of the females. Similar subtle differences between sexes in environmental sensitivities could eventually lead to population declines. </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="6294" page="69" related-article-type="in-this-issue" vol="353" xlink:href="10.1126/science.aaf2588">69</jats:related-article> ; see also p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6294" page="32" related-article-type="in-this-issue" vol="353" xlink:href="10.1126/science.aag1624">32</jats:related-article> </jats:p>

<jats:title>Fungi relieve nitrogen limitation</jats:title> <jats:p> Rising concentrations of atmospheric CO <jats:sub>2</jats:sub> stimulate plant growth; an effect that could reduce the pace of anthropogenic climate change. But plants also need nitrogen for growth. So far, experimental nitrogen addition has had equivocal effects on the magnitude of CO <jats:sub>2</jats:sub> fertilization. Terrer <jats:italic>et al.</jats:italic> explain that the impact of nitrogen on plant growth depends on the relationship between nitrogen availability and symbioses with mycorrhizal soil fungi. Only plants with ectomycorrhizal fungi associated with their roots can overcome nitrogen limitation. </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="6294" page="72" related-article-type="in-this-issue" vol="353" xlink:href="10.1126/science.aaf4610">72</jats:related-article> </jats:p>

<jats:p> Understanding how animals respond to atmospheric conditions across space is critical for understanding the evolution of flight strategies and long-distance migrations. We studied the three-dimensional movements and energetics of great frigate birds ( <jats:italic>Fregata minor</jats:italic> ) and showed that they can stay aloft for months during transoceanic flights. To do this, birds track the edge of the doldrums to take advantage of favorable winds and strong convection. Locally, they use a roller-coaster flight, relying on thermals and wind to soar within a 50- to 600-meter altitude band under cumulus clouds and then glide over kilometers at low energy costs. To deal with the local scarcity of clouds and gain longer gliding distances, birds regularly soar inside cumulus clouds to use their strong updraft, and they can reach altitudes of 4000 meters, where freezing conditions occur. </jats:p>

<jats:title>Spatial structure of RNA expression</jats:title> <jats:p> RNA-seq and similar methods can record gene expression within and among cells. Current methods typically lose positional information and many require arduous single-cell isolation and sequencing. Ståhl <jats:italic>et al.</jats:italic> have developed a way of measuring the spatial distribution of transcripts by annealing fixed brain or cancer tissue samples directly to bar-coded reverse transcriptase primers, performing reverse transcription followed by sequencing and computational reconstruction, and they can do so for multiple genes. </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="6294" page="78" related-article-type="in-this-issue" vol="353" xlink:href="10.1126/science.aaf2403">78</jats:related-article> </jats:p>

<jats:title>Stargazin and the AMPA receptor</jats:title> <jats:p> AMPA-subtype ionotropic glutamate receptors (AMPARs) mediate fast excitatory neurotransmission and contribute to higher cognitive processes such as learning and memory. In the brain, AMPARs exist as protein-protein complexes with various auxiliary subunits that tightly control AMPAR trafficking, gating, and pharmacology. Disruption of these complexes is implicated in numerous psychiatric and neurodegenerative diseases. Twomey <jats:italic>et al.</jats:italic> used cryo-electron microscopy to solve the structure of an AMPAR complex with stargazin (STZ), the major representative of transmembrane AMPAR regulatory proteins. STZ controls AMPAR synaptic targeting, synaptic plasticity, compartment-specific activity, pharmacology, and gating. </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="6294" page="83" related-article-type="in-this-issue" vol="353" xlink:href="10.1126/science.aaf8411">83</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>