Catálogo de publicaciones - revistas

<jats:title>Switching how to make flagella beat</jats:title> <jats:p>Motile cilia and flagella are hairlike cellular appendages that power the movement of individual cells or liquid across tissues, as exemplified by the cilia found in airways. The question of how they move in rhythmic oscillations has puzzled scientists for centuries. Lin and Nicastro used cryo–electron tomography (cryo-ET) to visualize the activity states of individual dynein motors with respect to their locations within beating flagella. They observed an asymmetric distribution of dynein activity and the switching of conformations of dyneins and their regulators between opposite sides of active flagella. The results confirm the switching aspect of the prevailing “switch-point” hypothesis but change the view with respect to how dynein activities are coordinated to drive flagellar motility.</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" related-article-type="in-this-issue" xlink:href="10.1126/science.aar1968">eaar1968</jats:related-article> </jats:p>

<jats:title>Hop, skip, jump, or massive leap</jats:title> <jats:p> In biological and engineered systems, an inherent trade-off exists between the force and velocity that can be delivered by a muscle, spring, or combination of the two. However, one can amplify the maximum throwing power of an arm by storing the energy in a bow or sling shot with a latch mechanism for sudden release. Ilton <jats:italic>et al.</jats:italic> used modeling to explore the performance of motor-driven versus spring-latch systems in engineering and biology across size scales. They found a range of general principles that are common to animals, plants, fungi, and machines that use elastic structures to maximize kinetic energy. </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" related-article-type="in-this-issue" xlink:href="10.1126/science.aao1082">eaao1082</jats:related-article> </jats:p>

<jats:p> “Our nation is moving toward two societies, one black, one white—separate and unequal.” So concluded a 1968 report by the Kerner Commission, established by U.S. President Lyndon Johnson to investigate the race riots of 1967. Not only did the report shine a spotlight on America's unfulfilled promises, it spurred action by politicians and policy-makers. Fifty years later, it is fair—and necessary—to ask if anything has changed. <jats:italic>Healing Our Divided Society</jats:italic> , the 2018 sequel to the Kerner report, argues sadly that gains of the 1970s and early 1980s are evaporating or reversing. But, noting the role of empirical evidence in bolstering past reforms, the new report suggests hopefully that “the quantity and sophistication of scientific information available today far exceeds what was available [in 1968].” </jats:p>

<jats:p>A roundup of weekly science policy and related news.</jats:p>

<jats:p>Modern humans and even Neandertals may have plied the Mediterranean long ago.</jats:p>