Catálogo de publicaciones - revistas

<jats:title>Monitoring Land Use</jats:title> <jats:p> Land-use decisions are based largely on agricultural market values. However, such decisions can lead to losses of ecosystem services, such as the provision of wildlife habitat or recreational space, the magnitude of which may overwhelm any market agricultural benefits. In a research project forming part of the UK National Ecosystem Assessment, <jats:bold> Bateman <jats:italic>et al.</jats:italic> </jats:bold> (p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6141" page="45" related-article-type="in-this-issue" vol="341" xlink:href="10.1126/science.1234379">45</jats:related-article> ) estimate the value of these net losses. Policies that recognize the diversity and complexity of the natural environment can target changes to different areas so as to radically improve land use in terms of agriculture and greenhouse gas emissions, recreation, and wild species habitat and diversity. </jats:p>

<jats:title>Cool Accretion</jats:title> <jats:p> Numerical models predict that in order to keep forming stars, galaxies should be continuously replenished with gas from the intergalactic medium. Using data from the Very Large Telescope in Chile, <jats:bold> Bouché <jats:italic>et al.</jats:italic> </jats:bold> (p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6141" page="50" related-article-type="in-this-issue" vol="341" xlink:href="10.1126/science.1234209">50</jats:related-article> ) report observations that are consistent with accretion of cold, chemically pristine gas onto a star-forming galaxy at a time when the cosmic star-formation activity was at its peak. </jats:p>

<jats:title>Mysterious Radio Bursts</jats:title> <jats:p> It has been uncertain whether single, short, and bright bursts of radio emission that have been observed are celestial or terrestrial in origin. <jats:bold> Thornton <jats:italic>et al.</jats:italic> </jats:bold> (p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6141" page="53" related-article-type="in-this-issue" vol="341" xlink:href="10.1126/science.1236789">53</jats:related-article> ; see the Perspective by <jats:bold> <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6141" page="40" related-article-type="in-this-issue" vol="341" xlink:href="10.1126/science.1240618">Cordes</jats:related-article> </jats:bold> ) report the detection of four nonrepeating radio transient events with millisecond duration in data from the 64-meter Parkes radio telescope in Australia. The properties of these radio bursts indicate that they had their origin outside our galaxy, but it is not possible to tell what caused them. Because the intergalactic medium affects the characteristics of the bursts, it will be possible to use them to study its properties. </jats:p>

<jats:title>Distorted Nanoparticle</jats:title> <jats:p> Nanoparticles have found many applications in modern technology; however, the full characterization of individual particles is challenging. One of the most interesting mechanical properties is the particle's response to lattice distortion. This property has been probed for ensembles of nanoparticles, but the required averaging may distort the results. <jats:bold> Clark <jats:italic>et al.</jats:italic> </jats:bold> (p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6141" page="56" related-article-type="in-this-issue" vol="341" xlink:href="10.1126/science.1236034">56</jats:related-article> , published online 23 May; see the Perspective by <jats:bold> <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6141" page="36" related-article-type="in-this-issue" vol="341" xlink:href="10.1126/science.1240500">Hartland and Lo</jats:related-article> </jats:bold> ) were able to image the generation and subsequent evolution of coherent acoustic phonons from an individual perturbed gold nanocrystal on the picosecond time scale. </jats:p>

<jats:title>Quantum Handedness</jats:title> <jats:p> When a rotating object is placed in circulating fluid, an imbalance of pressures on either side of it causes a deflecting force called the Magnus force. The quantum analog of this effect has been predicted to appear in the low-temperature A phase of <jats:sup>3</jats:sup> He, where the Cooper pairs forming the superfluid have a specific handedness. An impurity traveling through such a superfluid would experience a deflecting force in the direction determined by the chirality of the pairs. <jats:bold> Ikegami <jats:italic>et al.</jats:italic> </jats:bold> (p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6141" page="59" related-article-type="in-this-issue" vol="341" xlink:href="10.1126/science.1236509">59</jats:related-article> ) trapped impurities beneath the free surface of <jats:sup>3</jats:sup> He, set them in motion, and demonstrated the existence of this deflecting force by measuring the differential transverse current. The sign of the deflection varied over different cooling runs, indicating that the system was choosing one or the other chirality upon entering the superfluid phase—a signature of spontaneous symmetry breaking. </jats:p>

<jats:title>A Nonclassical Conclusion</jats:title> <jats:p> The concept of valence, which underlies the Periodic Table, originated in studies of reactivity rather than structure. Nonetheless, when studies in the mid-20th century suggested that the transient norbornyl cation (C <jats:sub>7</jats:sub> H <jats:sub>11</jats:sub> <jats:sup>+</jats:sup> ) reacted as though a carbon center had adopted a formally pentacoordinate motif, this nonclassical structural hypothesis engendered tremendous controversy. <jats:bold> Scholz <jats:italic>et al.</jats:italic> </jats:bold> (p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6141" page="62" related-article-type="in-this-issue" vol="341" xlink:href="10.1126/science.1238849">62</jats:related-article> ) have now succeeded in characterizing the norbornyl cation by x-ray crystallography and confirm the symmetrical fivefold motif. </jats:p>

<jats:title>Early Farmers?</jats:title> <jats:p> What was the role of the eastern Fertile Crescent (which includes southeastern Turkey, northeastern Iraq, and western Iran) in the transition from foraging to farming? <jats:bold> Riehl <jats:italic>et al.</jats:italic> </jats:bold> (p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6141" page="65" related-article-type="in-this-issue" vol="341" xlink:href="10.1126/science.1236743">65</jats:related-article> ; see the Perspective by <jats:bold> <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6141" page="39" related-article-type="in-this-issue" vol="341" xlink:href="10.1126/science.1240496">Willcox</jats:related-article> </jats:bold> ) investigated an archaeobotanical assemblage from Chogha Golan, in modern Iran over an apparently continuous occupation of the site over 2000 years, which captures the transition from foraging to farming. The rich archaeobotanical remains suggest the use of a wide array of plant species, including the progenitors of key crop plants (wheat, barley, and large-seeded legumes). Residents of the eastern Fertile Crescent thus appear to have been involved in plant management and possibly in the domestication of wild crop plants. </jats:p>

<jats:title>This Is the Place</jats:title> <jats:p> Bats, bees, seals, and many seabirds practice central-place foraging, leaving a central home site, such as a hive or a rookery, to forage in a specific territory. Such species also share the challenge of competing for local resources with individuals from separate colonies. Using satellite tags, <jats:bold> Wakefield <jats:italic>et al.</jats:italic> </jats:bold> (p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6141" page="68" related-article-type="in-this-issue" vol="341" xlink:href="10.1126/science.1236077">68</jats:related-article> , published online 6 June; see the Perspective by <jats:bold> <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6141" page="35" related-article-type="in-this-issue" vol="341" xlink:href="10.1126/science.1240316">Weimerskirch</jats:related-article> </jats:bold> ) followed over 180 northern gannets to determine potential drivers of foraging territory division. Boundaries among colonial territories arose as a result of competition with individuals from other territories. Individuals from the same colony appeared to share information about foraging sites, presumably contributing to the establishment and maintenance of specific, long-term colonial territories. </jats:p>

<jats:title>Female Infertility</jats:title> <jats:p> Anovulation, the failure of a woman's ovary to release an oocyte, is a major cause of female infertility. The mechanisms of ovulation have been studied extensively, with the hypothalamicpituitary axis serving as a key player in its regulation. <jats:bold> Hasuwa <jats:italic>et al.</jats:italic> </jats:bold> (p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6141" page="71" related-article-type="in-this-issue" vol="341" xlink:href="10.1126/science.1237999">71</jats:related-article> , published online 13 June) describe a mechanism by which anovulation can be caused by the disruption of two microRNAs that are expressed in the pituitary gland. </jats:p>

<jats:title>Form and Function</jats:title> <jats:p> The contribution of disulfide bonding to oxidative protein folding and assembly, quality control, and stress responses in the endoplasmic reticulum (ER) are widely recognized. In contrast, catalysis of disulfide bond formation downstream of the ER is uncharted territory. QSOX, a Golgi-localized or secreted disulfide catalyst, was identified in the 1970s and was more recently shown to be upregulated in many cancers. However, the physiological importance of QSOX catalytic activity has been unclear. <jats:bold> Ilani <jats:italic>et al.</jats:italic> </jats:bold> (p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6141" page="74" related-article-type="in-this-issue" vol="341" xlink:href="10.1126/science.1238279">74</jats:related-article> , published online 23 May) found that human QSOX1 is essential for incorporation of laminin into the extracellular matrix, with profound effects on the capability of the matrix to support integrin-mediated cell adhesion and migration. </jats:p>