Catálogo de publicaciones - revistas

<jats:title>Majorana on a hinge</jats:title> <jats:p> One of the early proposals for the physical implementation of Majorana zero modes (MZMs) centered on inducing superconductivity in a topological insulator (TI) by placing it in contact with a superconductor. Jäck <jats:italic>et al.</jats:italic> used scanning tunneling spectroscopy to observe MZMs in a similar heterostructure. In their devices, the TI is a hexagonal bismuth island placed on top of a layer of superconducting niobium. The bismuth island had topological boundary hinge states on every other edge of the hexagon. Placing a cluster of iron atoms on the hinge generated a zero-bias peak characteristic of MZMs at the interface between the cluster and the hinge state. </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="6447" page="1255" related-article-type="in-this-issue" vol="364" xlink:href="10.1126/science.aax1444">1255</jats:related-article> </jats:p>

<jats:title>Nacre-inspired toughened glass</jats:title> <jats:p> Nacre is a biological composite that is present in seashells. This composite contains a small amount of organic material that toughens brittle ceramics, such that a highly regular three-dimensional brick-and-mortar assembly of microscopic mineral tablets is bonded together with biopolymers. Synthetic nacres have not been able to capture the large-scale sliding of the bricks that is key to enhancing toughness. Yin <jats:italic>et al.</jats:italic> applied this model to toughening glass, where square or hexagonal borosilicate glass sheets were bonded together using ethylene-vinyl acetate interlayers (see the Perspective by Datsiou). This generated a structure that allows glass plates to slide past each other. The resulting five-layered glass composite was deformable and impact resistant, while maintaining high stiffness, flexural strength, surface hardness, and transparency. </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="6447" page="1260" related-article-type="in-this-issue" vol="364" xlink:href="10.1126/science.aaw8988">1260</jats:related-article> ; see also p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6447" page="1232" related-article-type="in-this-issue" vol="364" xlink:href="10.1126/science.aax9677">1232</jats:related-article> </jats:p>

<jats:title>Clustering vortices</jats:title> <jats:p> Many-body systems generally become more disordered as more energy is pumped into them. A curious exception to this rule was predicted in the context of turbulent flow by the physical chemist Lars Onsager. He suggested that the entropy of certain two-dimensional (2D) systems can decrease with increasing energy, corresponding to an effective negative temperature. Using 2D Bose-Einstein condensates of atoms, Gauthier <jats:italic>et al.</jats:italic> and Johnstone <jats:italic>et al.</jats:italic> put Onsager's theory to the test. They provided energy to the system by perturbing the condensate, creating vortices and antivortices. With increasing energy, the system became more ordered as clusters containing either only vortices or only antivortices emerged. </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="6447" page="1264" related-article-type="in-this-issue" vol="364" xlink:href="10.1126/science.aat5718">1264</jats:related-article> , p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6447" page="1267" related-article-type="in-this-issue" vol="364" xlink:href="10.1126/science.aat5793">1267</jats:related-article> </jats:p>

<jats:title>Clustering vortices</jats:title> <jats:p> Many-body systems generally become more disordered as more energy is pumped into them. A curious exception to this rule was predicted in the context of turbulent flow by the physical chemist Lars Onsager. He suggested that the entropy of certain two-dimensional (2D) systems can decrease with increasing energy, corresponding to an effective negative temperature. Using 2D Bose-Einstein condensates of atoms, Gauthier <jats:italic>et al.</jats:italic> and Johnstone <jats:italic>et al.</jats:italic> put Onsager's theory to the test. They provided energy to the system by perturbing the condensate, creating vortices and antivortices. With increasing energy, the system became more ordered as clusters containing either only vortices or only antivortices emerged. </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="6447" page="1264" related-article-type="in-this-issue" vol="364" xlink:href="10.1126/science.aat5718">1264</jats:related-article> , p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6447" page="1267" related-article-type="in-this-issue" vol="364" xlink:href="10.1126/science.aat5793">1267</jats:related-article> </jats:p>

<jats:title>Brain changes after overeating</jats:title> <jats:p> A brain region called the lateral hypothalamic area is an integral node in the neurocircuitry controlling feeding behavior. In a mouse model of obesity, Rossi <jats:italic>et al.</jats:italic> found that a distinct class of neurons within this region acts as a brake on feeding, suppressing food intake (see the Perspective by Borgland). These neurons were potently and uniquely modified by diet-induced obesity. Thus, discrete populations of lateral hypothalamic area neurons are fundamental regulators of feeding behavior that might be targeted to treat eating disorders. </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="6447" page="1271" related-article-type="in-this-issue" vol="364" xlink:href="10.1126/science.aax1184">1271</jats:related-article> ; see also p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6447" page="1233" related-article-type="in-this-issue" vol="364" xlink:href="10.1126/science.aay0204">1233</jats:related-article> </jats:p>

<jats:title>Rethinking primary visual cortex function</jats:title> <jats:p> Understanding how color is coded in the brain is central to vision research. The presently dominant model suggests that color and orientation are separately extracted in the primate primary visual cortex. These characteristics are thought to be represented by neurons located in different cortical columns that project separately to higher visual areas for further processing. Working with macaques, Garg <jats:italic>et al.</jats:italic> recorded from thousands of neurons using two-photon calcium imaging with single-neuron resolution. Nearly half of sampled hue-selective neurons responded more strongly to equiluminant colored stimuli than to full-contrast achromatic stimuli. A majority of strongly color-preferring neurons were also orientation selective. Processing of orientation and color is thus combined at the earliest stages of visual processing, which challenges existing models. </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="6447" page="1275" related-article-type="in-this-issue" vol="364" xlink:href="10.1126/science.aaw5868">1275</jats:related-article> </jats:p>