Catálogo de publicaciones - revistas

<jats:title>Climate killed off the megafauna</jats:title> <jats:p> The causes of the Pleistocene extinctions of large numbers of megafaunal species in the Northern Hemisphere remain unclear. A range of evidence points to human hunting, climate change, or a combination of both. Using ancient DNA and detailed paleoclimate data, Cooper <jats:italic>et al.</jats:italic> report a close relationship between Pleistocene megafaunal extinction events and rapid warming events at the start of interstadial periods. Their analysis strengthens the case for climate change as the key driver of megafaunal extinctions, with human impacts playing a secondary role. </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="6248" page="602" related-article-type="in-this-issue" vol="349" xlink:href="10.1126/science.aac4315">602</jats:related-article> </jats:p>

<jats:title>A surprising immune twist for RORC</jats:title> <jats:p> The immune system needs its full array of soldiers—including cells and the molecules they secrete—to optimally protect the host. When this isn't the case, minor infections can become chronic or even deadly. Markle <jats:italic>et al.</jats:italic> report the discovery of seven individuals carrying loss-of-function mutations in RORC, which encodes the transcription factors RORγ and RORγT. These individuals lacked immune cells that produce the cytokine interleukin-17, causing them to suffer from chronic candidiasis. RORC-deficient individuals also exhibited impaired immunity to mycobacterium, probably due to reduced production of the cytokine interferon-γ, a molecule not known to require RORC for its induction. </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="6248" page="606" related-article-type="in-this-issue" vol="349" xlink:href="10.1126/science.aaa4282">606</jats:related-article> </jats:p>

<jats:title>Weyl physics emerges in the laboratory</jats:title> <jats:p> Weyl fermions—massless particles with half-integer spin—were once mistakenly thought to describe neutrinos. Although not yet observed among elementary particles, Weyl fermions may exist as collective excitations in so-called Weyl semimetals. These materials have an unusual band structure in which the linearly dispersing valence and conduction bands meet at discrete “Weyl points.” Xu <jats:italic>et al.</jats:italic> used photoemission spectroscopy to identify TaAs as a Weyl semimetal capable of hosting Weyl fermions. In a complementary study, Lu <jats:italic>et al.</jats:italic> detected the characteristic Weyl points in a photonic crystal. The observation of Weyl physics may enable the discovery of exotic fundamental phenomena. </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="6248" page="613" related-article-type="in-this-issue" vol="349" xlink:href="10.1126/science.aaa9297">613</jats:related-article> and <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6248" page="622" related-article-type="in-this-issue" vol="349" xlink:href="10.1126/science.aaa9273">622</jats:related-article> </jats:p>

<jats:title>Cementing Roman concrete to a caldera</jats:title> <jats:p>Ancient concrete would seem to have little to do with volcano geology. However, Vanorio and Kanitpanyacharoen found similarities between the caprock of the Campi Flegrei caldera near Naples, Italy, and the Roman-era concrete for which the region was known. Both materials require a similar set of chemical reactions to give it the high strength caused by microstructures of intertwining fibrous minerals. The high strength of the natural rock explains the ability of the caldera to withstand periods of high-rate uplift without eruption. The Romans living in the caldera, where the town of Pozzuoli is today, may have been trying to mimic nature to produce this iconic material.</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="6248" page="617" related-article-type="in-this-issue" vol="349" xlink:href="10.1126/science.aab1292">617</jats:related-article> </jats:p>