Catálogo de publicaciones - revistas

<jats:p>A sugar molecule plays an unexpected role in controlling gene silencing by modifying repressor proteins.</jats:p>

<jats:p>Insights into El Niño's spatial structure may help to predict its effect on Atlantic tropical cyclones.</jats:p>

<jats:title>Did I Really Do That?</jats:title> <jats:p> Most of us believe that our daily actions occur because we exert conscious effort to make them happen; nevertheless, we sometimes seem to end up doing the precise thing we had hoped to avoid. <jats:bold>Wegner</jats:bold> (p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" page="48" related-article-type="in-this-issue" vol="325" xlink:href="10.1126/science.1167346">48</jats:related-article> ) reviews the recent psychological research on ironic processes. The findings support the view that the unwanted outcomes are held in working memory and that the monitoring centers that usually ensure correct behavior can be distracted or exhausted, allowing the taboo idea to escape. </jats:p>

<jats:p>Fruit-eating birds inhibit seed predation by beetles, a mechanism that is destabilized when disturbance opens the forest canopy.</jats:p>

<jats:title>Card Sorting Monkeys</jats:title> <jats:p> Single-neuron studies in primates help to establish a detailed understanding of cognitive processing and to provide an experimental base for understanding the cognitive deficits incurred by patients who have suffered damage to areas of the brain. <jats:bold> Buckley <jats:italic>et al.</jats:italic> </jats:bold> (p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" page="52" related-article-type="in-this-issue" vol="325" xlink:href="10.1126/science.1172377">52</jats:related-article> ) present the results of an intensive behavioral analysis of a group of monkeys bearing lesions to distinct areas of the prefrontal lobe. The Wisconsin Card Sorting Task is widely used in the clinic to assess the flexible learning of abstract rules. In the primates, a functional dissociation was observed across three regions: the principal sulcus, the orbitofrontal cortex, and the anterior cingulate cortex. This set of results contributes to the ongoing discussion of goal-directed behavior and serves to bridge neuropsychological studies in human patients and neurophysiological studies in primates. </jats:p>

<jats:title>Phoenix Ascending</jats:title> <jats:p> The Phoenix mission landed on Mars in March 2008 with the goal of studying the ice-rich soil of the planet's northern arctic region. Phoenix included a robotic arm, with a camera attached to it, with the capacity to excavate through the soil to the ice layer beneath it, scoop up soil and water ice samples, and deliver them to a combination of other instruments—including a wet chemistry lab and a high-temperature oven combined with a mass spectrometer—for chemical and geological analysis. Using this setup, <jats:bold> Smith <jats:italic>et al.</jats:italic> </jats:bold> (p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" page="58" related-article-type="in-this-issue" vol="325" xlink:href="10.1126/science.1172339">58</jats:related-article> ) found a layer of ice at depths of 5 to 15 centimeters, <jats:bold> Boynton <jats:italic>et al.</jats:italic> </jats:bold> (p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" page="61" related-article-type="in-this-issue" vol="325" xlink:href="10.1126/science.1172768">61</jats:related-article> ) found evidence for the presence of calcium carbonate in the soil, and <jats:bold> Hecht <jats:italic>et al.</jats:italic> </jats:bold> (p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" page="64" related-article-type="in-this-issue" vol="325" xlink:href="10.1126/science.1172466">64</jats:related-article> ) found that most of the soluble chlorine at the surface is in the form of perchlorate. Together these results suggest that the soil at the Phoenix landing site must have suffered alteration through the action of liquid water in geologically the recent past. The analysis revealed an alkaline environment, in contrast to that found by the Mars Exploration Rovers, indicating that many different environments have existed on Mars. Phoenix also carried a lidar, an instrument that sends laser light upward into the atmosphere and detects the light scattered back by clouds and dust. An analysis of the data by <jats:bold> Whiteway <jats:italic>et al.</jats:italic> </jats:bold> (p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" page="68" related-article-type="in-this-issue" vol="325" xlink:href="10.1126/science.1172344">68</jats:related-article> ) showed that clouds of ice crystals that precipitated back to the surface formed on a daily basis, providing a mechanism to place ice at the surface. </jats:p>

<jats:title>Phoenix Ascending</jats:title> <jats:p> The Phoenix mission landed on Mars in March 2008 with the goal of studying the ice-rich soil of the planet's northern arctic region. Phoenix included a robotic arm, with a camera attached to it, with the capacity to excavate through the soil to the ice layer beneath it, scoop up soil and water ice samples, and deliver them to a combination of other instruments—including a wet chemistry lab and a high-temperature oven combined with a mass spectrometer—for chemical and geological analysis. Using this setup, <jats:bold> Smith <jats:italic>et al.</jats:italic> </jats:bold> (p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" page="58" related-article-type="in-this-issue" vol="325" xlink:href="10.1126/science.1172339">58</jats:related-article> ) found a layer of ice at depths of 5 to 15 centimeters, <jats:bold> Boynton <jats:italic>et al.</jats:italic> </jats:bold> (p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" page="61" related-article-type="in-this-issue" vol="325" xlink:href="10.1126/science.1172768">61</jats:related-article> ) found evidence for the presence of calcium carbonate in the soil, and <jats:bold> Hecht <jats:italic>et al.</jats:italic> </jats:bold> (p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" page="64" related-article-type="in-this-issue" vol="325" xlink:href="10.1126/science.1172466">64</jats:related-article> ) found that most of the soluble chlorine at the surface is in the form of perchlorate. Together these results suggest that the soil at the Phoenix landing site must have suffered alteration through the action of liquid water in geologically the recent past. The analysis revealed an alkaline environment, in contrast to that found by the Mars Exploration Rovers, indicating that many different environments have existed on Mars. Phoenix also carried a lidar, an instrument that sends laser light upward into the atmosphere and detects the light scattered back by clouds and dust. An analysis of the data by <jats:bold> Whiteway <jats:italic>et al.</jats:italic> </jats:bold> (p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" page="68" related-article-type="in-this-issue" vol="325" xlink:href="10.1126/science.1172344">68</jats:related-article> ) showed that clouds of ice crystals that precipitated back to the surface formed on a daily basis, providing a mechanism to place ice at the surface. </jats:p>

<jats:title>Phoenix Ascending</jats:title> <jats:p> The Phoenix mission landed on Mars in March 2008 with the goal of studying the ice-rich soil of the planet's northern arctic region. Phoenix included a robotic arm, with a camera attached to it, with the capacity to excavate through the soil to the ice layer beneath it, scoop up soil and water ice samples, and deliver them to a combination of other instruments—including a wet chemistry lab and a high-temperature oven combined with a mass spectrometer—for chemical and geological analysis. Using this setup, <jats:bold> Smith <jats:italic>et al.</jats:italic> </jats:bold> (p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" page="58" related-article-type="in-this-issue" vol="325" xlink:href="10.1126/science.1172339">58</jats:related-article> ) found a layer of ice at depths of 5 to 15 centimeters, <jats:bold> Boynton <jats:italic>et al.</jats:italic> </jats:bold> (p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" page="61" related-article-type="in-this-issue" vol="325" xlink:href="10.1126/science.1172768">61</jats:related-article> ) found evidence for the presence of calcium carbonate in the soil, and <jats:bold> Hecht <jats:italic>et al.</jats:italic> </jats:bold> (p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" page="64" related-article-type="in-this-issue" vol="325" xlink:href="10.1126/science.1172466">64</jats:related-article> ) found that most of the soluble chlorine at the surface is in the form of perchlorate. Together these results suggest that the soil at the Phoenix landing site must have suffered alteration through the action of liquid water in geologically the recent past. The analysis revealed an alkaline environment, in contrast to that found by the Mars Exploration Rovers, indicating that many different environments have existed on Mars. Phoenix also carried a lidar, an instrument that sends laser light upward into the atmosphere and detects the light scattered back by clouds and dust. An analysis of the data by <jats:bold> Whiteway <jats:italic>et al.</jats:italic> </jats:bold> (p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" page="68" related-article-type="in-this-issue" vol="325" xlink:href="10.1126/science.1172344">68</jats:related-article> ) showed that clouds of ice crystals that precipitated back to the surface formed on a daily basis, providing a mechanism to place ice at the surface. </jats:p>

<jats:title>Phoenix Ascending</jats:title> <jats:p> The Phoenix mission landed on Mars in March 2008 with the goal of studying the ice-rich soil of the planet's northern arctic region. Phoenix included a robotic arm, with a camera attached to it, with the capacity to excavate through the soil to the ice layer beneath it, scoop up soil and water ice samples, and deliver them to a combination of other instruments—including a wet chemistry lab and a high-temperature oven combined with a mass spectrometer—for chemical and geological analysis. Using this setup, <jats:bold> Smith <jats:italic>et al.</jats:italic> </jats:bold> (p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" page="58" related-article-type="in-this-issue" vol="325" xlink:href="10.1126/science.1172339">58</jats:related-article> ) found a layer of ice at depths of 5 to 15 centimeters, <jats:bold> Boynton <jats:italic>et al.</jats:italic> </jats:bold> (p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" page="61" related-article-type="in-this-issue" vol="325" xlink:href="10.1126/science.1172768">61</jats:related-article> ) found evidence for the presence of calcium carbonate in the soil, and <jats:bold> Hecht <jats:italic>et al.</jats:italic> </jats:bold> (p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" page="64" related-article-type="in-this-issue" vol="325" xlink:href="10.1126/science.1172466">64</jats:related-article> ) found that most of the soluble chlorine at the surface is in the form of perchlorate. Together these results suggest that the soil at the Phoenix landing site must have suffered alteration through the action of liquid water in geologically the recent past. The analysis revealed an alkaline environment, in contrast to that found by the Mars Exploration Rovers, indicating that many different environments have existed on Mars. Phoenix also carried a lidar, an instrument that sends laser light upward into the atmosphere and detects the light scattered back by clouds and dust. An analysis of the data by <jats:bold> Whiteway <jats:italic>et al.</jats:italic> </jats:bold> (p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" page="68" related-article-type="in-this-issue" vol="325" xlink:href="10.1126/science.1172344">68</jats:related-article> ) showed that clouds of ice crystals that precipitated back to the surface formed on a daily basis, providing a mechanism to place ice at the surface. </jats:p>

<jats:title>A Hole New Approach</jats:title> <jats:p> Quantum dots can behave as artificial atoms, exhibiting a ladder of quantized energy levels with the number of electrons added to the dot being controllable. They are thus being extensively studied for application in the likes of quantum information processing strategies. However, the electrons interact with their environment and quickly lose their coherence properties. <jats:bold> Brunner <jats:italic>et al.</jats:italic> </jats:bold> (p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" page="70" related-article-type="in-this-issue" vol="325" xlink:href="10.1126/science.1173684">70</jats:related-article> ; see the Perspective by <jats:bold> <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" page="42" related-article-type="in-this-issue" vol="325" xlink:href="10.1126/science.1176296">Kolodrubetz and Petta</jats:related-article> </jats:bold> ) now show that if the charge of the dot is manipulated so that it is positive; that is, populated with a single hole, then the coherence properties of the dot can be extended. The strategy of using holes instead of electrons may provide a solution to the decoherence problem. </jats:p>