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<jats:p>Case It!, an IBI prize–winning module, provides computer simulations that enable student analysis of biological materials not usually available in laboratories.</jats:p>

<jats:p> A monthly roundup of recent news and projects of <jats:italic>Science</jats:italic> 's publisher, the American Association for the Advancement of Science. </jats:p>

<jats:title>Insights into Type 2 Immunity</jats:title> <jats:p> Different pathogens trigger characteristic immune responses. Although the immune responses against many bacteria, viruses, and fungi are relatively well understood, those against parasitic worms—termed type 2 responses—are much less so. Intriguingly, type 2 responses also mediate responses to allergens and allergic asthma. <jats:bold>Pulendran and Artis</jats:bold> (p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" page="431" related-article-type="in-this-issue" vol="337" xlink:href="10.1126/science.1221064">431</jats:related-article> ) review progress in understanding the signals that trigger type 2 immunity and the cellular responses that these responses initiate. </jats:p>

<jats:p> As <jats:italic>Neocapritermes taracua</jats:italic> termites age, they develop a suicidal toxic apparatus that bursts during aggressive encounters. </jats:p>

<jats:title>The Male Wiring Diagram</jats:title> <jats:p> The function of the nervous system is thought to represent an emergent property of its network connectivity. However, there are few complete descriptions of all the physical connections between neurons within a real nervous system. Working in nematodes, <jats:bold> Jarrell <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="437" related-article-type="in-this-issue" vol="337" xlink:href="10.1126/science.1221762">437</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="6093" page="416" related-article-type="in-this-issue" vol="337" xlink:href="10.1126/science.1225853"> <jats:bold>Chklovskii and Bargmann</jats:bold> </jats:related-article> </jats:bold> ) identified the complete connectome—every single chemical and gap junction synapse—of the tail ganglia, which govern mating behavior. </jats:p>

<jats:title>Star Partners</jats:title> <jats:p> Stars more massive than eight times the mass of the Sun are rare and short-lived, yet they are fundamentally important because they produce all the heavy elements in the universe, such as iron, silicon, and calcium. <jats:bold> Sana <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="444" related-article-type="in-this-issue" vol="337" xlink:href="10.1126/science.1223344">444</jats:related-article> ) examined the properties of a sample of ∼70 massive stars in six stellar clusters located nearby in our galaxy. Over half of the stars in the sample belong to a binary system and, during the course of their lifetimes, most of the stars in these binaries will interact with one another, either by merging or exchanging mass. Binary interaction may thus affect the evolution of the majority of massive stars. </jats:p>

<jats:title>Fiber with a Twist</jats:title> <jats:p> Optic fibers provide the backbone of communication networks. Controlling light propagation through the fiber is key to maximizing the capacity of information flow. By introducing a literal twist on the photonic crystal fiber, <jats:bold> Wong <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="446" related-article-type="in-this-issue" vol="337" xlink:href="10.1126/science.1223824">446</jats:related-article> ) show that adding chirality to the cladding surrounding the core may provide another route to manipulating the transmission of light. Coupling between the twisted cladding and the core results in dips in the transmission spectrum, which are dependent on the degree of twist introduced into the fiber. Such twisted microstructure fibers may offer opportunities for coupling, filtering and manipulating light. </jats:p>

<jats:title>Going Green with Nanophotonics</jats:title> <jats:p> Plasmons are optically induced collective electronic excitations tightly confined to the surface of a metal, with silver being the metal of choice. The subwavelength confinement offers the opportunity to shrink optoelectronic circuits to the nanometer scale. However, scattering processes within the metal lead to losses. <jats:bold> Lu <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="450" related-article-type="in-this-issue" vol="337" xlink:href="10.1126/science.1223504">450</jats:related-article> ) developed a process to produce atomically smooth layers of silver, epitaxially grown on silicon substrates. A cavity in the silver layer is capped with a SiO insulating layer and an AlGaN nanorod was used to produce a low-threshold emission at green wavelengths. </jats:p>

<jats:title>Getting Packed</jats:title> <jats:p> If one neglects the role of specific interactions, the packing of similar-shaped objects will depend only on the particular shape of the object. <jats:bold> Damasceno <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="453" related-article-type="in-this-issue" vol="337" xlink:href="10.1126/science.1220869">453</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="6093" page="417" related-article-type="in-this-issue" vol="337" xlink:href="10.1126/science.1226162">de Graaf and Manna</jats:related-article> </jats:bold> ) present computer simulations of the behavior of different types of polyhedra with simple and complex shapes that are packed under thermal equilibrium into various structures, from crystals to amorphous materials through liquid crystals. Despite the wide variety of starting shapes, the packing behavior could be quantitatively described using just two criteria; one for the particle shape as a function of its volume and surface area, and one for the number of nearest neighbors. </jats:p>

<jats:title>Getting to Know Titan</jats:title> <jats:p> Gravity-field measurements provide information on the interior structure of planets and their moons. <jats:bold> Iess <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="457" related-article-type="in-this-issue" vol="337" xlink:href="10.1126/science.1219631">457</jats:related-article> ; published online 28 June) analyzed gravity data from six flybys of Saturn's moon, Titan, by the Cassini spacecraft between 2006 and 2011. The data suggest that Titan's interior is flexible on tidal time scales with the magnitude of the observed tidal deformations being consistent with the existence of a global subsurface water ocean. </jats:p>