Catálogo de publicaciones - revistas

<jats:title>Transforming nitrogen without carbon</jats:title> <jats:p> How much carbon does it take to make nitric acid? The counterintuitive answer nowadays is quite a lot. Nitric acid is manufactured by ammonia oxidation, and all the hydrogen to make ammonia via the Haber-Bosch process comes from methane. That's without even accounting for the fossil fuels burned to power the process. Chen <jats:italic>et al.</jats:italic> review research prospects for more sustainable routes to nitrogen commodity chemicals, considering developments in enzymatic, homogeneous, and heterogeneous catalysis, as well as electrochemical, photochemical, and plasma-based approaches. </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.aar6611">eaar6611</jats:related-article> </jats:p>

<jats:p>Chisholm and Fung claim that our method of estimating conspecific negative density dependence (CNDD) in recruitment is systematically biased, and present an alternative method that shows no latitudinal pattern in CNDD. We demonstrate that their approach produces strongly biased estimates of CNDD, explaining why they do not detect a latitudinal pattern. We also address their methodological concerns using an alternative distance-weighted approach, which supports our original findings of a latitudinal gradient in CNDD and a latitudinal shift in the relationship between CNDD and species abundance.</jats:p>

<jats:p> LaManna <jats:italic>et al</jats:italic> . (Reports, 30 June 2017, p. 1389) claim that subadult trees are proportionally less common at high conspecific adult density (CNDD) and that this effect increases toward the tropics and for rare species. We show that the CNDD-abundance correlation may have arisen from a methodological artifact and that a range of processes can explain the reported latitudinal pattern. </jats:p>

<jats:title>Mapping the planarian transcriptome</jats:title> <jats:p> A cell type's transcriptome defines the active genes that control its biology. Two groups used single-cell RNA sequencing to define the transcriptomes for essentially all cell types of a complete animal, the regenerative planarian <jats:italic>Schmidtea mediterranea.</jats:italic> Because pluripotent stem cells constantly differentiate to rejuvenate any part of the body of this species, all developmental lineages are active in adult animals. Fincher <jats:italic>et al.</jats:italic> determined the transcriptomes for most, if not all, planarian cell types, including some that were previously unknown. They also identified transition states and genes governing positional information. Plass <jats:italic>et al.</jats:italic> used single-cell transcriptomics and computational algorithms to reconstruct a lineage tree capturing the developmental progressions from stem to differentiated cells. They could then predict gene programs that are specifically turned on and off along the tree, and they used this approach to study how the cell types behaved during regeneration. These whole-animal transcriptome “atlases” are a powerful way to study metazoan biology. </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.aaq1736">eaaq1736</jats:related-article> , 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.aaq1723">eaaq1723</jats:related-article> </jats:p>

<jats:p>Next month, Canada will host the Group of 7 (G7) summit in picturesque Charlevoix, Québec. As leaders from Canada, France, Germany, Italy, Japan, the United Kingdom, and the United States come together, along with European Union representatives, to discuss the progressive agenda, science will be on everyone's mind. With science and technology playing a prominent role in everyday life, access to science education and to science-based careers is ever more essential for inclusive growth and for women's empowerment.</jats:p>

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

<jats:p>Projects will offer "public access" in bid for support from astronomy community.</jats:p>